Paleoimaging: Field Applications for Cultural Remains and Artifacts

Paleoimaging

Ronald G. Beckett Quinnipiac University Hamden, Connecticut, USA

Gerald J. Conlogue Quinnipiac University Hamden, Connecticut, USA with a Foreword by

Andrew J. Nelson, Ph.D.

Boca Raton London New York

CRC Press is an imprint of the Taylor & Francis Group, an informa business

CRC Press Taylor & Francis Group 6000 Broken Sound Parkway NW, Suite 300 Boca Raton, FL 33487-2742 © 2010 by Taylor and Francis Group, LLC CRC Press is an imprint of Taylor & Francis Group, an Informa business No claim to original U.S. Government works Printed in the United States of America on acid-free paper 10 9 8 7 6 5 4 3 2 1 International Standard Book Number: 978-1-4200-9071-0 (Hardback) This book contains information obtained from authentic and highly regarded sources. Reasonable efforts have been made to publish reliable data and information, but the author and publisher cannot assume responsibility for the validity of all materials or the consequences of their use. The authors and publishers have attempted to trace the copyright holders of all material reproduced in this publication and apologize to copyright holders if permission to publish in this form has not been obtained. If any copyright material has not been acknowledged please write and let us know so we may rectify in any future reprint. Except as permitted under U.S. Copyright Law, no part of this book may be reprinted, reproduced, transmitted, or utilized in any form by any electronic, mechanical, or other means, now known or hereafter invented, including photocopying, microfilming, and recording, or in any information storage or retrieval system, without written permission from the publishers. For permission to photocopy or use material electronically from this work, please access www.copyright.com (http:// www.copyright.com/) or contact the Copyright Clearance Center, Inc. (CCC), 222 Rosewood Drive, Danvers, MA 01923, 978-750-8400. CCC is a not-for-profit organization that provides licenses and registration for a variety of users. For organizations that have been granted a photocopy license by the CCC, a separate system of payment has been arranged. Trademark Notice: Product or corporate names may be trademarks or registered trademarks, and are used only for identification and explanation without intent to infringe. Library of Congress Cataloging-in-Publication Data Beckett, Ronald G. Paleoimaging : field applications for cultural remains and artifacts / Ronald G. Beckett, Gerald J. Conlogue. p. cm. Includes bibliographical references and index. ISBN 978-1-4200-9071-0 (hardcover : alk. paper) 1. Imaging systems in archaeology. I. Conlogue, Gerald J. II. Title. CC79.I44B43 2010 930.1--dc22 Visit the Taylor & Francis Web site at http://www.taylorandfrancis.com and the CRC Press Web site at http://www.crcpress.com

2009028071

Dedication

Since this text is the culmination of over 40 years as a radiographer, the ἀrst dedication is to those radiographers, Ray Gagnon, Marty Ricart, Bob Pooler, and Charlie Maccalous, who were not only my teachers, demonstrating the science and art of radiography, but also instilled the spirit that anything is possible. To Drs. E. Leon Kier and John Ogden, who taught me how to formulate and carry out research. To the late Dr. Tony Bravo, who showed me not only courage in the face of death, but also how to enjoy life. To my son Byron, his wife Nicole, my daughter Keanau, and my son Michael, who continue to be very accepting of my eccentricities. Last, but certainly not least, to Shar Walbaum whose encouragement, conἀdence, and belief in my pursuits are ultimately responsible for my success and this book. Gerald Conlogue This book is further dedicated to those many individuals who have helped me to develop not only my endoscopic skills but also those who have enhanced my understanding of pathophysiology among the living. LeRoy Johansen, Steven McPherson, Bud Spearman, Robert Kaczmarek, Dean Hess, and Harold McAlpine, who collectively showed me how to be a respiratory therapist, to never be satisἀed with the status quo, and provided a model to follow in research and scholarly work. To Drs. William Ludt and Michael McNamee, who constantly challenged my understanding of clinical medicine and disease states and encouraged me to know more. To Ralph “Buster” Beckett whose early 20th century work in agricultural research sparked my desire to understand the world around me. To my parents, Howard and Terry & Beckett, who taught me how to “play in the sand”, no matter how old I was. To my sons Matthew, Paul, and James, and my daughter Julie, who have been so very supportive of my interests and efforts and from whom I have and continue to learn so much. And to my wife Katherine Harper-Beckett, who has supported not only this project but held me up on so many occasions with her quite strength and sincere belief in me. I am forever blessed. Ronald Beckett

Table of Contents

Foreword Preface Acknowledgments Contributing Author

ix xi xvii xix

Section I Paleoimaging Multimodalities

1

Photography for Paleoimaging

3

Ronald Beckett and Gerald Conlogue

2

Conventional Radiography

19

Gerald Conlogue and Ronald Beckett

3

Computer-Based Imaging

123

Gerald Conlogue, Ronald Beckett, and John Posh

4

Endoscopy: Field and Laboratory Application of Videoendoscopy in Anthropological and Archaeological Research

185

Ronald Beckett and Gerald Conlogue

Section II Paleoimaging Standards

5

Radiographic Procedures and Standards

233

Gerald Conlogue and Ronald Beckett

6

Endoscopic Procedures and Standards Ronald Beckett and Gerald Conlogue

vii

245

viii Table of Contents

Section III Artifact Analysis

7

Paleoimaging the Internal Context

265

Ronald Beckett and Gerald Conlogue

8

Paleoimaging the External Context

293

Ronald Beckett and Gerald Conlogue

9

Paleoimaging Objects Out of Context

311

Gerald Conlogue and Ronald Beckett

Section I V Safety in the Field Setting

10

Field Paleoimaging Safety and Health Challenges

339

Ronald Beckett

11

Radiation Protection and Safety

355

Gerald Conlogue

Appendices Appendix A: Recording Form for Radiographic Examination of Mummified or Skeletal Remains and Artifacts

365

Appendix B: Recording Form for Endoscopic Examination of Mummified or Skeletal Remains

369

Appendix C: Example of Risk Assessment Documentation

373

Appendix D: Expedition Kit List—Papua New Guinea

385

Appendix E: Statement of Health

387

Index

391

Foreword

Archaeology is necessarily a destructive science, as the very process of excavation involves the removal of objects from their original context; however, the archaeological team seeks to maximize the nondestructive recovery of information at every step along the way from discovery, to analysis, to conservation. The capture of images of cultural remains and artifacts—paleoimaging—is central to that process. In this book, Beckett and Conlogue call upon their considerable hands-on experience to provide an in-depth examination of the three most important imaging techniques, photography, radiography, and endoscopy, and explain how these techniques can be applied to all aspects of archaeological and artifactual analysis. Other authors have touched on individual aspects of this subject matter, but this is the first volume to provide the rationale and methodology for each technique and to synthesize them in one place. As such it is a tremendously valuable resource. There are several significant themes that run throughout this volume that are worth emphasizing in this foreword. They are the importance of teamwork, the concept of multimodal imaging, and the effective use of technology. I will address these themes in sequence.

Teamwork Archaeology, from prospection to excavation, to analysis, to conservation, to exhibition, is a multidisciplinary undertaking that requires coordinated contributions from many people with many different skill sets. Beckett and Conlogue highlight the paleoimaging team, consisting of paleoimagers and paleoimaging interpreters; however, they make the observation that there are very few people who are specialized in either area. Thus, this volume plays an extremely important role in developing the paleoimaging team, as it provides a common language that radiologists, archaeologists, biological anthropologists, and radiological technicians can use. A common language leads to effective communication and helps coordinate efforts to achieve a common goal.

Multimodality Beckett and Conlogue emphasize the term multimodal imaging, suggesting that each imaging technique adds new elements to the process of information recovery. Unfortunately, many archaeologists are not familiar with radiography or endoscopy, so these techniques are underutilized in the discipline. This volume provides clear explanations of the value of each imaging modality as well as the equipment required and the methods utilized. Thus, it will play an important role in expanding the analytical horizons of archaeologists everywhere. Beyond the basics of each imaging modality an equally important contribution of this volume is its emphasis on creativity in terms of how the modalities are deployed. For instance, there are very few radiological technologists who would think of taking a ix

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clinically obsolete x-ray machine to the field, to power it using generators and converters, and to set up a dark room in a tent. Likewise, not many pulmonologists would think of lowering their endoscopes into unopened tombs. Beckett and Conlogue are masters at the creative application of their skills and equipment; they are genius lateral thinkers, and they are the consummate problem solvers. The reader who pays particular attention to this creativity will get the most out of this volume.

Effective Use of Technology Mummies have been front and center in the imaging world from the time of the discovery of x-rays and through every advance in radiological technology. The recent arrival of the latest 256 slice CT scanner in a U.S. hospital was celebrated by scanning a mummy as the first “patient.” The appeal of “high tech” has led to the common perception that other methods of imaging have become obsolete. However, nothing could be further from the truth. As Beckett and Conlogue ably demonstrate, simple equipment can be utilized to capture vital information, particularly in field situations. Furthermore, a familiarity with basic imaging techniques is a requirement to fully understand and exploit the advanced capabilities of digital imaging. Thus, newer is not necessarily better, and the most effective paleoimaging team will consider all available imaging methods.

Beckett and Conlogue There are no two scholars who are better qualified to write this book. I can attest from personal experience that there are no others I would rather have on a field project. I have seen first-hand their teamwork ethos, their creativity and adaptability, and their ability to use the simplest equipment to the maximum effect. They have traveled the world x-raying and endoscoping mummies of commoners, monks, and saints; they have imaged Peruvian whistling pots, Chinese porcelain vases, and sideshow curios; they have worked in tombs, labs, and museums, and they have communicated the results of their work in the popular media, in the classroom, and in scholarly works. This volume is a compendium of a vast body of personal experience and two lifetimes dedicated to bringing their skills and enthusiasm to the service of archaeology. This book will find a prominent place on the shelves of archaeologists, anthropologists, radiological technicians, physicians, museologists, conservators, and interested individuals from many other walks of life. Andrew J. Nelson, PhD Bioarchaeologist Associate Professor of Anthropology University of Western Ontario London, Ontario Research Associate Royal Ontario Museum Toronto, Canada

Preface

Background and Rationale Medical and industrial imaging methods have the potential to be powerful tools in both the documentation and data collection procedures found in many nontraditional settings. Each technology described in this text has been applied to alternate settings, such as mummified human remains, soon after its historical development. In addition to providing useful data for analysis, these powerful tools have the added benefit of being nondestructive, thereby preserving the remains or artifacts for future analysis with yet to be developed technologies. The authors began this work to provide a basis for understanding the field application of various imaging modalities in bio-anthropological settings. However, these imaging modalities have also been applied in studies of non-biological specimens. Section III, Artifact Analysis, has been included to present the broader application potential of these imaging methods. An array of imaging methods has been employed in anthropological and archaeological research. When applied individually, certain information can be obtained. When applied in a complementary manner, not only can additional data be collected, but also the relationships among those data may often enhance our understanding of the meaning of their associations. In the recent past, literature referred to the use of a single imaging method or modality, such as x-ray, endoscopy, or computed tomography (CT) scans. More recently, scientific papers and presentations have adopted the term multimodal imaging. Since each modality has advantages and disadvantages, most researchers support the construct that no single modality can obtain all the data possible from a given subject. Therefore, multiple imaging methods need to be applied in an attempt to maximize data collected and to enhance the interpretability of those data. Conventional, or standard x-rays (radiographs), yield a two-dimensional image of three-dimensional objects. In addition, the images have the associated problems of superimposition of shadows, an inability to differentiate structures of similar densities, magnification, and distortion. Without creative application technique a standard x-ray cannot provide data describing the true spatial relationship of an object or organic feature within the broader context of the body as a whole. Conventional radiography does, however, have the potential to be highly portable and can yield much information that would be otherwise unobtainable. Radiography is ideally suited for the field research environment. Endoscopy can complement the radiograph, providing an image with shape, contour, color, and location of what was only a shadow on the x-ray. Additionally, the endoscope can be used to guide instruments for retrieval of tissues or artifacts from within a closed environment, such as a body cavity, coffin, or tomb. The instrumentation is portable and well suited for field imaging studies. xi

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If the subject of the study can be moved, computed tomography (CT) could be employed to better reveal the spatial relationships within the subject. The CT scan can also guide biopsy or artifact retrieval procedures. Although “portable” CT scanners exist, their size and the logistics of terrain often result in limited availability in remote field settings. In addition, the hardware and software of these units place limitations on the type of data obtainable. The data collected by the more recently introduced multidetector CT (MDCT) scanner, once stored, can be reformatted to view the study object from multiple planes and generate 3-D representations of those data. The 3-D image can be of the object as a whole or feature a single organ, structure, or artifact associated with the subject. The data may also be animated to rotate the object for multi-directional viewing and analysis. Computed radiography (CR) and direct digital radiography (DR) have the advantage of being filmless systems that allow manipulation of the displayed image to improve the image exposure, possibly revealing otherwise “invisible” structures. Since CR and DR generate 2-D images, superimposition of shadows and many of the other disadvantages associated with conventional radiography are still problematic. Magnetic resonance imaging (MR) has also found its way into the anthropological arena and adds data otherwise unobtainable by the other mentioned modalities. Unlike the other modalities described, x-rays are not involved in the production of MR images. High intensity magnetic fields are manipulated to, most commonly, measure the “mobile” hydrogen content of the object under investigation. Like the CT instrumentation, MR imaging requires the study subject to be brought to an imaging or research facility. Photographic documentation and analysis is another mode applied in the paleoimaging setting. Standard and filtered photographs allow for continued indirect visual analysis once the researcher has departed the original research site. Newer photographic methods can produce 3-D representations of surface characteristics allowing the researcher to view surface features from various angles. Each of the tools in the multimodal-imaging arsenal comes with its unique application limitations. For example, CT scanners are quite large and weighty, making them difficult to apply in field or remote settings. Additionally, CT scans have the potential to produce tremendous numbers of images, many of which contribute little to the study. Endoscopy requires an access route. Conventional or computed radiography, while portable, produces 2-D images. The use of the term multimodal therefore indicates the natural evolution of imaging in anthropological and archaeological research, moving from specific single modality imaging studies to those that incorporate several imaging methods. Collectively, multimodal imaging, when applied to anthropological and archaeological research, has come to be known as “paleoimaging.” The term paleo refers to studies involving ancient, prehistoric, primitive, or early structures or cultures. However, the term paleoimaging has been generalized to a broader context to include not only prehistoric subjects but also the analysis of historic human or animal remains, associated artifacts, and in archaeological applications. The data collected through paleoimaging methods have been applied using both the medical approach, where the study subjects are transported to an imaging facility and, in contrast, the anthropological approach, where the subjects are examined in or very near the original context. In anthropological and archaeological research context is critical. The burial location, relationship and position of objects, and burial goods are all critical data requiring analysis within or as close to the original context as possible. Once an object, such as mummified

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human remains, is moved, the context is altered. Not only the relationship among related objects, buildings, and tombs, but what is held within a mummy bundle or within the mummy itself, too, can be disturbed, further altering the internal context. Whenever possible, researchers would do well to employ in context field imaging methodology for initial data collection. In context field imaging demonstrates the nondestructive nature of the described modalities and is the main focus of this book. Once the object is moved from its original context, the nondestructive nature of a study is jeopardized. The actual act of moving the object may in fact be destructive. If the use of advanced imaging, such as a CT scan, is warranted, the decision to transport the subject to an imaging facility needs to be based upon the safety of the study subject and what additional data the advanced imaging may add to the case at hand. If on-site field imaging is conducted, those data can contribute to the risk/ benefit decision of whether or not to move the object for more advanced imaging.

Standards: Methods and Procedures Another critical issue surrounding paleoimaging research is that of methodological and procedural standards. Many reports in the literature often omit specific details regarding technical factors, such as radiographic exposure settings, data recording media, specific instrumentation, or endoscopic lenses used as related to the imaging data collected. Another issue is that many who are new to the paleoimaging arena may be experienced at gathering data and interpreting images produced from living subjects but not from mummified remains. Mummies, for the most part, are completely desiccated. The desiccation process, as well as many artificial preparation procedures creating that mummy, alters the manner in which imaging data can be attained for maximal interpretability. Collecting images that call for a new exposure setting or positioning approach may not be considered due to a lack of experience in operating the equipment in archaeological or anthropological contexts. Interpretation, too, can be challenging to the untrained eye. The morphologic changes seen in organ systems among the varied mummification processes, for example, may lead to misinterpretation of the significance of structures by someone who is accustomed to interpreting images from hydrated, living patients. In Paleoimaging: Field Applications for Cultural Remains and Artifacts, Section II, Paleoimaging Standards, the authors offer application standards for the varied imaging modalities as applied to this specific line of research. The methodological and procedural standards offered in this text are intended to assist researchers in obtaining the desired data in an accurate, efficient, and reproducible manner.

Artifact Imaging The paleoimaging techniques described in this text have a natural application in the imaging of non-biological cultural artifacts. Section III, Artifact Analysis, of Paleoimaging: Field Applications for Cultural Remains and Artifacts demonstrates how multimodal imaging can assist nondestructive data collection in an archaeological context. Imaging applications to help discover such variables as ceramic construction and technology complexity, orientation and composition of grave goods, temporal context based on artifact analysis,

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differentiation between authentic and fraudulent artifacts, and imaging works of art for conservation purposes are described.

Safety in Field Paleoimaging Projects Radiation safety and field safety concerns presented in Section IV, Safety Concerns in the Field, describe the application and situational variables that will allow safe data collection in challenging field settings. The radiation safety and field safety discussions are intended to provide those involved in field imaging projects with the basic understanding of the safety issues at hand as well as practical means of preparing for and conducting paleoimaging studies in a safe and responsible manner.

The Paleoimaging Team—A Brief Discourse Bioanthropological and bioarchaeological research naturally calls upon the skills of various scientists from many disciplines. Among those disciplines are those individuals skilled in paleoimaging. When considering the data attainable from the varied imaging studies applied to the anthropological and archaeological setting, several variables need to be considered: the data collection or paleoimaging process, recalibration of those processes for additional data collection, and the interpretation of these data. It would seem logical then that to conduct such research one would need someone to collect the data, a paleoimager, and someone to interpret the data. While this may seem straightforward, it is the opinion of the authors that the researchers filling these roles should have special qualifications. Paleoimagers (Data Collectors) Paleoimagers need to be experienced in the examination of naturally and intentionally mummified animal and human remains, and various types of artifacts. Collecting the data requires skills related to radiographic exposure settings, positioning, familiarity with morphologic variations seen associated with varied mummification methods, recording media, and data collection manipulation skills. These skills should also include an understanding of what data need to be collected given the research objectives and with careful consideration of the context. For example, setting the exposure variables and selecting the type of film and film holder to image the bony skeleton within a mummy bundle would likely not visualize desiccated organ remnants inside the mummy. Exposure variables set to pick up features of the integument would also reveal features of the wrappings. Knowing when and how to use imaging modalities to best acquire the desired images requires creativity and skillful application of the many exposure and positioning variables. Additionally, the individual must possess the skills and knowledge necessary to override preset protocols built into the software of sophisticated instrumentation designed to image living hydrated patients in medical settings. It is, therefore, a combination of skills required that are associated with the practice of radiography, coupled with knowledge of anthropological variations and the significance of nuances in the data collected. A paleoimager, as it relates to radiographic data collection, should be a radiologic technologist who has been mentored by a seasoned field paleoimager and bioanthropologist as there are no

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current preparation programs for this growing field. The individual needs to be trained in multiple modalities, the medical and industrial applications of those modalities, and well versed in the limitations of each modality. Further, the individual needs to be an expert in cross-sectional anatomy and be familiar with pathological conditions and the signs those conditions may leave behind in mummified tissue. Another required attribute is that the individual be technically adept and creative as much of the research is conducted in remote areas without reliable electricity sources or water, thus requiring instrument modification adapting to the given situation. Critical thinking is paramount. Endoscopic data collection needs to be conducted by an individual familiar with the many technical variables associated with these procedures. The individual needs to have a working knowledge of the instrumentation possibilities including both medical and industrial tools. Media archiving skills are also important. Biopsy techniques and artifact retrieval skills are necessary as these techniques are often specific to the research objectives. An understanding of anatomy and physiology is critical as is the understanding of pathological changes in organs and tissues. Further, an understanding of the varied morphologic changes seen among various mummification practices is vital. This paleoimager, too, must be creative and adaptive to the varied research environments. In addition to the knowledge and skill base described, a seasoned field endoscopist and a bioanthropologist should mentor the individual in order to maximize the application of this modality. The importance of photographic documentation of paleoimaging research cannot be understated. The photographer need not only be an expert in photographic methods but also be well aware of what is critical information to document. Typically, the photographer is under the direction of the project coordinator, usually an anthropologist or bioarchaeologist. However, the ideal photographer would know what to photograph and when to photograph and blend in naturally with the workflow. The photographic documentation required includes, but is not limited to, contextual documentation, procedural documentation, scientific documentation, and an artful representation of the remains or artifacts under investigation.

Paleoimaging Interpreters Initially, it would seem that since much of the data collected is radiographic, a radiologist would be the logical individual to make the interpretations. While this may be true, there are very few true paleoradiologists available. In fact, there are no specialized training programs in this area of expertise. Too often a radiologist becomes a paleoradiologist as soon as she/he interprets her/his first mummy x-ray. Sadly, this oversimplifies the challenges faced in the interpretation of images produced from mummified human remains. The radiologist does possess the skills necessary for interpretation when the subjects are living hydrated patients. However, the morphologic changes seen among the varied mummification practices require the radiologist to be well versed in the processes of mummification and their effects on the human body. While the radiologist’s skills involving differential diagnosis are critical to the interpretation of data, the analyses should include consultation with a physical anthropologist, bioanthropologist, or bioarchaeologist as well as a paleopathologist. It is only with this expert input regarding such variables as cultural practices surrounding the mummification method, dietary habits of the culture, and knowledge of varied environmental impacts on human tissue over time, that differential diagnoses

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can more accurately be determined. The paleoimaging interpreters, then, should include the radiologist (mentored by bioanthropology, bioarchaeology, physical anthropology, and paleopathology), along with a bioanthropologist, physical anthropologist and/or a bioarchaeologist, and a paleopathologist who is well versed in imaging modalities. In summary, the ideal paleoimaging team would include a photographer, a radiographer, an endoscopist, a radiologist, a bioanthropologist or bioarchaeologist, a physical anthropologist, and a paleopathologist, all of whom would have specialty training and experience in the process of human mummification and its morphologic and taphonomic impact on the remains. Additional medical experts such as trauma physicians, orthopedists, pulmonary specialists, and dentists, as well as many others, should be available to enhance the interpretation of those data related to their area of expertise.

Summary Paleoimaging: Field Applications for Cultural Remains and Artifacts is a work intended to describe the strengths and limitations of imaging applications in varied nontraditional field settings. The text offers methodological and procedural standards for the application of these modalities as well as standards for interpretation of the collected data. The authors hope that this text will contribute to those researchers who desire to employ paleoimaging in their research projects. The text intends to contribute to the growing field of mummy science studies. The potential contribution of this work rests in the concept that the interpretation and understanding of ancient cultures can only be as good as the data collected.

Acknowledgments

All paleoimaging work is teamwork. We are fortunate to have been invited to collaborate on a great many research endeavors around the globe. A book like this would not have been possible without the assistance of a great number of individuals, private imaging facilities, and institutions. We need to acknowledge many researchers and colleagues from whom we have learned so very much about the exciting “time travel” we all get to experience through our common interests. In no particular order and our apologies to those inadvertently omitted: Mütter Museum: Gretchen Worden; Quinnipiac University: Joseph Woods, William Hennessy, Dennis Richardson, Tania Blyth, Jiazi Li, and Derik Weber; researchers in bioarchaeology and paleopathology: Gino Fornaciari, Anthony Bravo, Bob Brier, Roxy Walker, Andrew Nelson, Roger Colton, Janet Monge, Lisa Schwappach, Sonia Guillen, Bernardo Arriaza, Arthur Aufderheide, Larry Cartmell, and Alana CordeCollins; Slater Memorial Museum, Norwich Free Academy, Norwich, Connecticut; Susan Frankenbach, Vivian F. Zoe, and Alexandra Allardt; Advance Radiology Consultants, Fairfield, Connecticut: Monique LeHardy, Amy Kovac, Andrea Mel, and Dennis Condon; Barnum Museum: Kathy Maher; Toshiba American Medical Systems: Mark Hatin; Madison Radiology, Old Lyme, Connecticut: Anne Stebbins; Auman Funeral Home: Gary Double; Zoom Imaging: John Posh; Naugatuck Valley Associates: Dave Votto; Ripley’s Believe it or Not®: Edward Meyer and Barry Anderson; FUJIFILM NDT Systems: Bob Lombardo; University College, Dublin; Engel Entertainment (formerly Engel Brothers Media); National Geographic Channel (U.S.); National Geographic Channel International; Paleopathology Association; Yale Peabody Museum of Natural History; and Rosicrucian Egyptian Museum. Ronald Beckett and Gerald Conlogue

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Contributing Author and Reviewers

John Posh, RT (R), (MR)

Chief Veterinary MRI Technologist MRI Safety Officer Animal Scan LLC Senior Partner MRI Safety Specialist Bethlehem, Pennsylvania

Reviewers William F. Hennessy, MHS, RT (R), (M), (QM), OAP(C) Chairman, Department of Diagnostic Imaging Program Director of Diagnostic Imaging Assistant Professor of Diagnostic Imaging Quinnipiac University Hamden, Connecticut

Shelley L. Giordano DHSc, RT(R), (MR) Director of Academic and Clinical Coordination Graduate Radiologist Assistant Program Assistant Professor of Diagnostic Imaging Quinnipiac University Hamden, Connecticut

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I

Paleoimaging Multimodalities Introduction: Getting Started

The use of the term multimodalities is fairly self-explanatory when applied to paleoimaging. The term simply means using more than one imaging modality to derive the most usable data in an attempt to make accurate interpretations regarding past peoples and their cultures. Using the multimodal imaging approach in anthropology and archaeology is much like gathering evidence for a forensic case. The more evidence you have to support the suppositions as they relate to the case, the stronger the case. Unfortunately, no single imaging modality can give you all the information you need. In fact, relying on a single imaging modality may increase the incidence of misinterpretation. As is the case with all research, any new data acquired should give rise to many more questions. In paleoimaging, general questions arise from a data point derived from a single imaging modality and may include the following: How can we confirm what we think we are seeing? How can we use additional imaging to better inform our interpretations? Sometimes, the answer is the reapplication of that imaging mode, perhaps from a new projection angle. In other cases, the answer lies in using additional imaging methods to clarify and confirm the original data. Although more advanced imaging, such as computed tomography, is a useful approach to additional data collection, often conditions in field settings and the condition of human mummified remains or artifacts limits the transportation possibilities and, thereby, the application of additional imaging modes. Field settings often present situations in which there are limited resources. In these cases, the creativity of the paleoimaging team comes into play. Skilled paleoimagers who can apply the constructs of critical thinking, using what resources is available, are often able to collect additional applicable data that assist in the interpretation of the collected data. Also, using portable and complementary imaging modalities in the field can generate a tremendous amount of data for those interpretations. The paleoimaging multimodalities that have proved useful in anthropological and archaeological research are addressed in the first section of this book. These modalities include photographic techniques; conventional radiography; computerized imaging, such as computed radiography, direct radiography, computed tomography, and magnetic resonance; and varied endoscopic techniques. These imaging tools create a powerful means of collecting accurate data with little or no damage to the mummified remains or artifacts. Multimodal imaging, therefore, preserves the study subjects for future researchers using yet-to-be-developed data collection instrumentation. Although not all of the imaging modalities discussed in this section can be readily applied in the field, several can. Paleoimaging conducted at or near the original context has the potential to gather the most accurate imaging data as moving the study subject may create an alteration of the internal context, that is, the context within the mummy itself. In addition, 1

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Paleoimaging: Field Applications for Cultural Remains and Artifacts

data analysis in context enhances the ability of researchers to make crucial connections between and among the imaging data and the cultural setting, including burial inclusions. This section includes four chapters that introduce the reader to paleoimaging multimodalities including photography, conventional radiography, computerized imaging modalities, and endoscopy. The field applications and limitations of each modality are presented, and case examples are used when appropriate.

Photography for Paleoimaging

1

Ronald Beckett and Gerald Conlogue Contents Introduction Context Establishing Workflow Documenting Procedures Evidentiary Special Photographic Techniques Summary References

3 4 8 9 15 16 16 17

Introduction The relationship between photography and anthropology has been well established over many years. Before improvements in communications, photographs were how anthropologists and archaeologists could bring exciting and new information to Western cultures. Photographs were used by these disciplines to promote their work and to share scholarly information among the academic community (Edwards 1992). Photography was first used to simply present portraits of peoples or of landscapes, providing a context for those viewing the images. Soon, photography in anthropology came to be used as an instrument of representation (Collier and Collier 1986). Anthropology used photography in a methodological and prescribed manner. The intent was to document field findings with scientific objectivity. Today, many anthropologists and researchers from other disciplines, such as paleoimagers, have had little or no formal training in photography and assume that photography is a simple manner of point and shoot. However, when building a team for a field research project, current practice is to strive to engage trained photographers in order to provide accurate, complete, and usable images. The photographs are then combined with a narrative or text provided by the field anthropologist and other specialists to ensure that any photographs taken have a purpose beyond objectifying the subject. In this way, the field context can be captured and better communicated. Each discipline brings its special knowledge and skills to bear on a field research project. Photographers, too, have their place in fieldwork. Additionally, the continued development of digital photographic technology makes on-site instant image review possible. We begin this section with a chapter on photography because in paleoimaging research, we begin each procedure with direct visual observation. Photography, if conducted with skill, has the potential to augment our observational skills. It is beyond the scope of this chapter to delve deeply into the technologies and techniques of trained photographers. Nor do we intend to explore the philosophical aspects of field photography. Rather, it is the 3

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intent of this chapter to establish the importance of photography in relation to paleoimaging studies. On many occasions, reviewing paleoimaging data, such as radiographs and endoscopic images, after their initial collection provides the researchers an opportunity to examine those images in greater detail. The additional study of the images often results in finding features initially overlooked that are important to the case at hand. This is true for photography as well. The photograph can provide a wealth of information that is sometimes missed during the initial visual observation. The photographer should be a full member of the paleoimaging team. As the reader will see through the remainder of this chapter, the photographer will have specific required tasks intended to complement the paleoimaging study. The photographer should be well versed in the characteristics, requirements, operation, and limitations of the paleoimaging technologies employed. The photographer needs to be aware of the photographic requirements of the other paleoimaging team members. Additionally, the photographer should be adept at various photographic methods including filtered photography, macrophotography, scientific photography, and low-light photography. The photographer must also possess an understanding of the ancient cultural aspects of the particular study, which will serve to inform him or her about what is critical to document. Photography’s use as an adjunct to paleoimaging is less concerned with its place in visual anthropology and more focused on evidentiary documentation of subject, context, procedure, and modifications. This represents an objective application of photography rather than using as a tool to elicit some type of deep human response. With that said, photography as one of our multimodal tools in paleoimaging provides not only the scientific documentation required but also images that can move the heart.

Documenting Context The first role of photography as it relates to paleoimaging is to document the physical setting where the research will be conducted. The general environment associated with the study at hand should be photographed with respect to those environmental features that may impact the work to be done. In addition, the context from where the cultural remains or artifacts came is critical, as it may assist in the interpretation of paleoimaging data. The environmental conditions may help explain taphonomic characteristics of the cultural remains as artifacts and human and animal remains continue to interact with their environment over time (Aufderheide 2003; Figure  1.1). These photographs may include documentation of nearby waterways; urban sprawl; evidence of flood plains, landslides, or cave-ins; and documentation of current climatic characteristics, to name a few. Photographs of where the cultural material was found are also critical, as often a microclimate exists that can further explain the condition of the remains or artifacts. These photographs may include tombs, a cliffside, or other burial aspects such as wrappings and enclosures (Figures  1.2–1.5) that may have impacted mummification or the state of preservation of the remains. If radiographic or endoscopic images are later transported to specialists in other countries, photographs of the regional environmental conditions and the specific burial sites may be critical in interpreting what is seen on the paleoimaging data.

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Figure 1.1  (See color insert following page 12.) Photographs of regional environments that

may impact the mummification and preservation of cultural artifacts and remains. Shown here is a dry desert environment (left) and modern agriculture near ancient burial tombs (right) that may impact the water table.

Of equal importance is the photographic documentation of the specific paleoimaging environment, where the work is to be conducted. On many occasions, field paleoimaging is conducted in very tight settings such as in caves, tombs, and remote research facilities. Photographic documentation of these variables not only provides a record of the working conditions but also may assist future researchers who are planning a field paleoimaging project in the same or similar environment. Photographic documentation

Figure 1.2  (See color insert following page 12.) Photographic documentation of a subterranean tomb environment that may explain paleoimaging data.

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Figure 1.3  Photographic documentation of the opening to a cave that holds mummified Ibaloi remains in the Kabayan Jungle, Luzon, the Philippines.

of how logistical challenges were resolved is also a useful information to future research teams (Figure 1.6). Any feature of the environmental setting that may pose a safety risk should be photographed as well. Paths, walkways, stairs, ladders, streams, electrical supply outlets, and generators are just a few examples of what should be photographed in order to document the challenges and adaptations used to get the paleoimaging project under way. Following the documentation of context, the subjects of the study should be photographed from as many angles as possible. The varied views of the subjects provide paleoimagers with additional information from which to develop approaches to the imaging tasks at hand. The initial photographs are intended to be a general survey of the subjects. However, if a particular entrance route for the endoscopic procedure is seen, for example, it can be documented using appropriate photographic technique such as macrophotography. Later in the study, a more scientific or forensic approach will be used.

Figure 1.4  (See color insert following page 12.) Photographic documentation of Anga mummies placed on a cliff overlooking their village following mummification. The documentation helps explain the deterioration of the remains seen during paleoimaging research.

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Figure 1.5  Photographic documentation of textiles used on mummy bundles that serves to explain the level of mummification seen through paleoimaging. Grave goods are also documented.

The initial photographs of the subjects are critical to paleoimaging in that they serve to document the condition of the cultural material prior to the initiation of the work. Photographs documenting the condition of the study subjects are also recommended, ensuring that the paleoimaging process caused no damage. Of course, if the paleoimaging work did result in inadvertent damage to the subjects, this, too, should be photographed. The authors have learned that it is beneficial, whenever possible, to time- and date-stamp the photographs. On a paleoimaging project in Italy, the museum director suggested that our team had caused damage to a particular object (Figure 1.7). We were able to vindicate ourselves only because we had a professional photographer who, as part of the team, photographically documented the study subject with a time and date stamp prior to our initiation of any imaging studies. This time-and-date-stamped photograph provided the

Figure 1.6  Photographic documentation of logistic problem resolution. Shown here is a method devised to transport a gasoline generator used to power paleoimaging instrumentation at a remote cave site in the Kabayan Jungle, Luzon, the Philippines.

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Figure 1.7  Photographic documentation of the condition of a study subject prior to paleoimaging procedures. This prestudy photograph proved extremely useful to the team (see text).

necessary evidence showing that the condition of the subject was exactly the same before our research as it was after we had completed our study.

Establishing Workflow Another use of the initial photography is to employ the photographs to establish a workflow scheme for the paleoimaging study. The paleoimager should be with the photographer as these images are obtained. For example, the paleoimager may point out a specific area or location that may work well for the placement of a portable darkroom. The photographs can later be used to explain and communicate the thought process behind the establishment of the workflow for the particular project. The photographs may also serve to provide an assessment of the relationship between and among structural features at the research site. Once the instrumentation is set up, additional workflow documentation is required. Another aspect of workflow as it relates to photography is the role of the photographer during the paleoimaging procedures. A good photographer knows what photographs are required and how to get those photographs without being intrusive. In fact, if it’s a good photographer aware of and familiar with the workflow pattern, you may never know the photographer is there. This “invisibility” is dependent on the skill and experience of the photographer. If the photographer is a permanent member of the paleoimaging team, workflow patterns and relationships may develop naturally. With each team member focused on

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his or her individual unique tasks, enhanced workflow can mean increased efficiency with less loss of time waiting for a particular photograph to be taken.

Documenting Procedures Paleoimaging procedures should be shared with the scientific and academic communities in order to help validate, standardize, and demonstrate reproducible field methodology. A critical part of the field paleoimaging procedures naturally becomes photographic documentation. Photography is necessary to record the technological aspects of the research project. When coupled with images of the study context, photographs of the instruments used in that study are important in order to provide interested researchers with ideas of what types of paleoimaging tools work in what settings. For example, specific endoscopes are selected for specific endoscopic tasks. A small-diameter scope may be used when the opening into the cultural material is very small, while a very long endoscope (Figure 1.8) with supplementary illumination may be used to explore a tomb prior to excavation. The instruments used for each of these applications are unique. Photographs will provide a record of what instrument was matched to which task. Field paleoimaging contexts challenge paleoimagers with many varied situations and physical conditions in which to set up their instruments. Even within the same project, several setups or instrument configurations may be required to attain the desired view or projection. In order to explain exactly how an image was acquired, photographic documentation of the unique setups is required. Figure 1.9 shows a variety of setup situations for field paleoimaging equipment. These photographs will inform interested parties as to the possible equipment configurations when faced with a similar imaging challenge in a

Figure 1.8  Photographic documentation of a 30 ft (9.14 m) portable endoscope used for specific research. The photograph tells future researchers which specific technology was employed for a specific application.

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Figure 1.9  Photographic documentation of varied paleoimaging instrumentation setups. Top left: Endoscopy setup. Top right: Portable radiographic unit and image receptor in field setting. Bottom right: Fixed radiographic unit in a remote research facility. Bottom left: Unique instrument panel.

different setting. As you will read in Chapter 2, using native or local materials is often the best way to solve unique equipment setup problems. Of particular interest to field paleoimaging is the construction of a light-tight space for x-ray film loading and changing. Also, important is the film processing setup (Figure 1.10). Although the construction of darkrooms and film processing space is discussed in greater detail in Chapter 2, it is important to mention here the necessity of photographic documentation of these creations. Each field setting will be different from the last, and the more photographic documentation of these unique setups, the less time will be spent reinventing the process. Another important aspect of photography used in field paleoimaging is that of documenting specific techniques. Any unusual technique, such as a radiograph taken from 40 ft (12.19 m) away from the subject, should be photodocumented. Another example of a special technique would be the imaging of several objects placed on a single image receptor at one time (Figure 1.11). When a radiograph is reviewed for interpretation, the image can be somewhat abstract to those unfamiliar with looking at x-rays, particularly if they do not know or cannot discern the direction or distance from which the x-ray was taken. A photograph taken from the point of view (POV) of the x-ray tube is useful in providing anatomical orientation. The POV photograph coupled with the radiographic image helps lessen the potential of misinterpretation due to lack of proper orientation (Figure  1.12). In the case of endoscopic examination, the entry route into the cultural material must be photographed to orient individuals viewing the endoscopic images to the appropriate anatomical region being studied (Figure 1.13).

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Figure 1.10  Photographic documentation of (clockwise from top left) radiographic unit setup, x-ray film processing in darkroom, film rinsing station, and film drying method.

Any and all field paleoimaging procedures should be photographed in a pre- and postprocedure manner. In particular, any procedures that alter or have the potential to alter the cultural material in any way must be photographed in a pre- and postprocedure fashion. Since these photographs have great implications for future researchers,

Figure 1.11  Photographic documentation of a special radiographic procedure: imaging multiple artifacts on a single film.

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Figure 1.12  Photographic POV documentation serving to orient the viewer in order to assist with orientation and interpretation.

Figure 1.13  Photographic documentation of endoscopic entry routes used to orient the endoscopic image with the object.

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Figure 1.14  Photographic documentation of organic structure following removal from the original context. Shown here is abdominal and coprolite material with scale.

depending on the procedure, the pre- and postprocedure photograph series should be obtained with an orientation to scale. For example, if it is determined that an artificial opening is to be made in an attempt to biopsy material from within remains or artifacts, the procedure narrative must be accompanied with pre- and postprocedure artificial opening photographs. If the procedure involves an actual biopsy or artifact retrieval from within the remains, photographs of the retrieval should be taken. Photographs of the biopsied material or retrieved artifact should be taken once out of the remains or other context in a scientific manner, including orientation to scale (Figure 1.14). As previously stated, field paleoimaging presents researchers with many logistical and technological challenges. Each situation is unique and requires critical thinking and problem solving. Once the procedural problems are resolved, photographs of the technical improvisations may help future researchers who find themselves in similar situations. Often in field paleoimaging projects, the resultant image shows a unique object or structure that appears to be on the surface of the cultural material. Whenever possible, close-up or macrophotography of specific surface targets may be warranted. There are many indications for macrophotography from both an anthropological and archaeological perspective. What we are referring to here is the photographic documentation of those surface features that may explain images obtained through radiography, endoscopy, or advanced imaging modalities (Figure 1.15). For example, x-ray penetration through a set of human remains may have been impeded by sand or dried mud adhering to the part of the remains being imaged. A photographic record of the surface substance helps explain the “opacity” seen on the radiograph. In some cases, an x-ray will reveal a small metallic object often used as offerings or surface adornments in some ancient cultures (Figure 1.16). Due to the overall condition of the remains and the centuries of accumulated surface debris, the metallic object is not readily located visually. The radiograph tells the photographer

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Figure 1.15  (See color insert following page 12.) Macrophotography showing the details of

anatomical anomaly also seen on radiograph. The correlational analysis of the radiograph and the macrophotograph enhance the understanding of the anomaly. Also shown here is the use of “raking,” a lighting technique used to accentuate desired features.

where to search for the surface object and, if found, a macrophotograph can be taken to document the important feature (Figure 1.17). The importance of photography of the many technical aspects and procedures of field paleoimaging also serves to create a record of innovations and ideas that worked, as well as those that did not work. The pre- and postprocedure photographs are critical to the

Figure 1.16  Radiograph showing metallic adornments near the eyes of the mummified remains.

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Figure 1.17  (See color insert following page 12.) Macrophotographic documentation of the metallic structures over the eyes of the mummified remains. The radiograph alerted the photographer to the existence of the unique metallic object, which could then be located and documented.

documentation of the impact of paleoimaging. The surface macro and POV photography assist with the interpretability of the paleoimaging images and enhance the potential for differential diagnoses.

Forensic Photography Forensic photography has long used skilled photographers to document a wide variety of items or remains to be used as evidence in a criminal case. The forensic photographs require a strict adherence to undisturbed contexts and scientific photography. The anthropological and archaeological environments can be considered from the same point of view. In essence, the paleophotographer is collecting evidence from cases that have long gone cold. In addition, many artifacts and anatomical features require the paleophotographer to be skilled in scientific photographic methods. This would include the consideration of perspective in the photograph. In order to accomplish the goal of accurately photographing cultural material, care must be taken to remain scientific and not to objectify the remains or object. As previously discussed, macrophotography and photography of biopsied material or artifacts retrieved from within remains or bundles need to be photographed with orientation to scale. Many times, the biopsied material or artifacts are radiographed outside of the remains. The photograph with orientation to scale increases the interpretability of these images. Many archaeological items such as grave goods (Figure 1.18) or unique anthropological variations such as cranial modification need to be photographed with orientation to scale. These photographs can then be compared to the radiographs or endoscopic images of the same item or subject. If the paleoimaging project involves a museum, photographs taken that are associated with other paleoimaging data may also serve as a formal record of museum holdings and may be recorded in the museum catalog.

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Figure 1.18  Photographic documentation of grave goods with scale. Shown here is a nonperpendicular photograph demonstrating an error in photographic perspective.

Special Photographic Techniques During paleoimaging projects, unique features may be present on the cultural material. The importance of macrophotography has already been discussed. At times, remains are adorned with culturally significant tattoos. Standard photography may very well document the overall shape and configuration of the tattoo. Special photographic filtering techniques, such as infrared, can bring out the features of these tattoos, increasing the interpretability of the image. A variety of filters are available to the trained photographer, and their description and applications are beyond the scope of this chapter. Lighting techniques are also important for the paleophotographer. Portable adjustable lighting systems are used by paleophotographers to obtain macro- and nonmacrophotographs that are free from glare or flashback from strobes. Another lighting technique employed by the paleophotographer is to bring the light in from an angle, accentuating the subtle depth variations of the subject not seen on a photograph produced from straight on lighting. This lighting procedure is called raking. Raking can “bring out” important surface features on the cultural material, enhancing the data collected and increasing the interpretability (see Figure 1.15). In situations where no external light can be used, such as within a portable darkroom, the paleophotographer must be skilled in low-light or no-light photography.

Summary The relationship between photography and the documentation needs of paleoimaging research is clear. During a paleoimaging project, the photographer must be aware of what needs to be photographed and when. This knowledge comes only from fieldwork experience as a member of the paleoimaging team. We have used forensic photographers, as well as professional photographers experienced in archaeological and anthropological settings, as paleoimaging team members with excellent results. New photographers or student

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assistants may also function as the team photographer, only if the team anthropologist, paleoimagers, or a seasoned fieldwork photographer properly mentors them. A key point of this chapter is that there must be a team member who is responsible for the photographic needs of the team. Each team member has his or her own area of expertise. If a paleoradiographer or endoscopist also tries to be the team photographer, important information will potentially be missed. An individual dedicated to and skilled in photography will make critical contributions to the outcome of the paleoimaging research study.

References Aufderheihe, A. C. 2003. The Scientiἀc Study of Mummies. Cambridge: Cambridge University Press. Collier, J. and M. Collier. 1986. Visual Anthropology: Photography as a Research Method (revised and expanded edition). Albuquerque, New Mexico: University of New Mexico Press. Edwards, E. (ed.) 1992. Anthropology and Photography, 1860–1920. London: Royal Anthropological Institute.

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Gerald Conlogue and Ronald Beckett Contents Introduction Evolution of Conventional Radiography in Anthropology and Archaeology Background: Mummy Mania Begins Early Radiographic Applications: Exploring Possibilities Modern Radiographic Applications: Refinement and Technological Progress Conventional Radiography: The Basics Exposure Variables X-Ray Penetration Focal Spot Source-to-Image Distance Image Distortion Beam Collimation Image Receptor: Film and Screens Darkroom: Film Processing Field Radiography Applications: Considerations and Challenges General Considerations Field Imaging: Specific Considerations The Radiographic Unit Utilities X-Ray Tube Support System Image Receptors Darkrooms Film Drying and Viewing Instant Film Positioning Devices to Maintain the Position of the Remains Devices for Holding the Image Receptor Unique Technical Challenges Summary of Unique Technical Challenges Technical Advantages and Disadvantages of Conventional Radiography Technical Advantages Technical Disadvantages Complementary Data Acquisition Anthropological Applications: Laboratory and Field Objectives for Conventional Radiography Fundamental Objectives 19

20 21 21 21 22 23 23 23 27 28 28 29 29 33 34 34 35 35 36 37 39 42 49 50 56 62 64 65 88 89 89 90 90 91 91

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Assess Condition of the Remains or Artifact Age at the Time of Death Determination of Sex in Absence of Direct Observation Dentition Refinement Objectives Detection of Pathologies (Paleopathology) Target Identification for Biopsy and Retrieval Cultural Practices Temporal Context Mechanism of Death Summary and Future Applications References

91 91 92 94 95 95 99 108 118 119 119 119

Introduction Undeniably, one of the greatest medical advances during the 20th century was the development of radiography. The lives of countless individuals have been saved because physicians were able to “look” inside the patient with images produced by x-rays. Similarly, radiography has been an invaluable tool in archaeology and anthropology. The discipline of radiography has greatly expanded since Wilhelm Röntgen’s first public demonstration during the January 23, 1896 address to the Würzburg Physical Medical Society (Eisenberg 1992a). Today there are a number of modalities or methods under the broad area of radiography. Conventional, standard, or plain radiography are the commonly employed terms to identify the imaging modality that utilizes a basic x-ray source and film as the recording medium. It has been suggested that the optimal location for a conventional radiographic examination of archaeological and anthropological material is a hospital or research imaging facility (Chhem and Brothwell 2008a). However, since the modality has the advantage of being highly mobile, it has been easily applied in remote areas. Such portability makes conventional radiography a powerful field data acquisition method for anthropological and archaeological research. Based on experience, the authors have adopted the philosophy that skeletal and mummified remains should be imaged within or as close to the recovery site or storage facility as possible. Using field radiography as a primary approach, there is minimal disruption of the taphonomic context. Transporting mummified remains can alter the location of foreign bodies and/or artifacts within the mummy, complicating the interpretability and, therefore, the significance of those materials and their spatial associations. Transportation from remote locations to imaging facilities carries the added risk of physical damage to the often fragile remains. Additionally, field radiography has the potential to collect radiographic data from large populations of mummies, making it possible to conduct statistical analyses. Although population studies can be conducted at imaging facilities, it is logistically more challenging. Transportation of 200 mummies to a facility has not been reported in the literature. Radiographic examination in the field can also be used to triage a large group of remains in order to select those that would yield more data from advanced imaging modalities, such as computed tomography, and thus justify transportation to an imaging facility. Finally, due to the remoteness of many research locations, field radiography may be the only way to gather critical data and conduct imaging examinations.

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Although a more complete review can be found elsewhere (Böni et al. 2004; Chhem and Brothwell 2008b), this chapter will describe some of the contributions made by conventional radiography to anthropological and archaeological research from a historical perspective. The focus will be more on the discussion of the basics, equipment development, and the many variables related to the instrumentation challenges experienced during field applications. Further, this chapter will describe the manipulation of technical factors and the use of ancillary equipment that will increase the likelihood of acquiring diagnostically acceptable images. The chapter will also present the research objectives of conventional radiography in these field environments.

Evolution of Conventional Radiography in Anthropology and Archaeology Background: Mummy Mania Begins Mummy mania found its way into Western European culture in the mid- to late 1800s. Mummies or mummy parts from Egypt were purchased from mummy vendors on the streets of Cairo by European travelers and scientists. Ancient artifacts were brought back to America or Europe and became family heirlooms. These heirlooms eventually found their way into museums. However, a major problem associated with this type of mummy commerce and collection became apparent. A traveler or scientist could purchase a mummy with nice wrappings and place them in an unassociated coffin with well-preserved hieroglyphs. The mixing and matching that occurred at the time of purchase caused many curators and scientists to believe that the inscription on the coffin lid, which referred to the intended occupant, may in fact not be related in any way to the actual mummified remains inside. The problem of mismatched remains, artifacts, and coffins continues to challenge curators and historians today. Mummy mania was so prevalent that it was reported that mummies were used as medicine, paint pigment, fuel for steam locomotives, and for social events such as mummy unwrappings (Aufderheide 2003a). These unwrappings drew many observers. What was of great interest to the audience was not the human remains inside but rather the artifacts associated with the mummy, such as amulets and jewelry. Within the same time frame, mummies were being discovered in parts of the world other than Egypt. In the late 1800s, Max Uhle, considered the father of South American archaeology, was discovering mummies from a completely different part of the world (Aufderheide 2003b). Uhle’s work brought the world’s attention to places such as Bolivia and Peru, which were rich in mummified remains and artifacts. Mummies were everywhere, and radiography had played an important role in the scientific study of the mummified remains and their associated artifacts since the discovery of the x-ray. To place radiographic research and analysis in anthropology and archaeology in perspective, an understanding of the historical contributions made by researchers using radiography to study mummified remains and artifacts is warranted. Early Radiographic Applications: Exploring Possibilities On November 8, 1885, Wilhelm Conrad Röntgen accidentally discovered x-rays while working on a Crooke’s tube project. The first x-ray was taken of Bertha Röntgen’s hand, clearly showing her skeletal structures and her wedding band. The exposure time required

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was 15 min. Soon after Röntgen’s discovery, German physicist Carl George Walter Koenig published a paper in March of 1896 titled “14 Photographs with X-rays Taken by the Physical Society of Frankfurt am Main” in which he presented the first x-rays taken of mummified remains, including an Egyptian cat mummy and the knees of an Egyptian child mummy. That same year, a mummified bird was radiographed by Thurstan Holland. Another early use of radiography related to the study of mummified remains, reported in 1896 and in 1897 by Alexander Dedekind, was to use x-rays to distinguish between real and fake mummies. Also in 1897, Albert Londe radiographed a fake Japanese mummy and an authentic forearm and hand of an Egyptian mummy. Londe’s work demonstrated the value of seeing what is inside mummy wrappings without having to unwrap the remains. In May of 1897, Charles Lester Leonard and Stewart Culin radiographed a Peruvian mummy. Their work further demonstrated the ability to “see” within without having to unwrap. Culin reported that the mummy being studied was so fragile that unwrapping it would have destroyed it, supporting the use of radiographic examination not only to see what was inside but also to assess its state of conservation. Karl Gorjanovic-Kramberger used radiographic techniques in 1901 to examine hominid fossil teeth. Gorjanovic-Kramberger was attempting to develop a way to overcome the magnification found on radiographic images and established radiography as a nondestructive tool in phylogenetic analysis (Boni et al. 2004). Soon, the use of radiographic data was expanded to include not simply seeing inside the wrappings or to disclose frauds but also to collect anthropological and pathological data. In 1904, Gardiner radiographed mummies from the collection at the British Museum and reported the first use of radiographs to determine the age of a mummy’s bone and, therefore, the age at the time of death. Heinrich Ernst Albers-Schoenberg published a paper in 1905 describing an extensive radiographic examination of mummies and is credited with assessing soft tissues and dental pathology in mummies. This is one of the first reports to describe pathological conditions in mummified remains. Additional studies conducted in the early part of the 20th century further explored the varied uses of radiographs in anthropological settings. Each time a new imaging modality became available, it was applied to mummy studies shortly after its inception. Modern Radiographic Applications: Refinement and Technological Progress In 1973, James Harris and Kent Weeks published X-Raying the Pharaohs. In their book, the authors describe the expanded use of radiography in mummy research to examine such characteristics as diseases present, medical and dental problems, age at the time of death, cause of death, process of mummification, artifact analysis, and the impact of grave robbers and movement on the mummified remains. The works reported by Harris and Weeks were conducted at the Cairo Museum in Egypt and demonstrate the significance of conducting radiographic studies in the field. The damage done to mummified remains by transport and grave robbers makes a strong case for conducting radiographic studies in the field as near the original context as possible. Computed tomography and magnetic resonance imaging bring wonderful imaging potentials to the arenas of anthropological and archaeological research. Although these advanced imaging modalities offer remarkable data collection capabilities, the remains or artifacts under analysis need to be moved to the imaging facility, risking damage to the remains and possibly an alteration of biological or artifact spatial orientation within those remains. Although there are reports of advanced imaging being done in the field, these

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studies are expensive and logistically limiting. Conventional radiography technology can be very portable, allowing researchers to collect data at the original context, within a cave, a tomb, in a jungle or desert, or at remote research facilities (Conlogue et al. 2004). It is from these field applications that the most accurate radiographic data, free from “travel damage,” can be collected and, therefore, the most meaning made of those data. The remainder of this chapter will describe some of the basic principles of radiographic imaging and the application of conventional radiography in field settings. It is beyond the scope of this book to provide a comprehensive presentation of the physical basis of the principles of x-ray production. Readers interested in a more detailed discussion are directed elsewhere (Bushberg et al. 2002; Bushong 2008a). Because field imaging using conventional radiography is “unconventional,” many challenges can, and will, arise. These challenges are described, and solutions are discussed.

Conventional Radiography: The Basics Conventional radiography is still the method most frequently used to initially examine artifacts, victims for forensic examination, and mummified and skeletal remains. Since Röntgen’s 1895 discovery, many modifications have changed the design of x-ray equipment. However, the basic principles of x-ray production have remained unchanged. That is, within the x-ray tube, electrons are accelerated from the filament within the negative electrode, or cathode, to the target within the positive electrode, or anode. The interaction between the high-speed electrons and the target material produces x-rays. Exposure Variables X-Ray Penetration There are several variables that are manipulated in the production of x-rays. The penetrating ability of the x-ray beam is controlled by the acceleration of the electrons across the tube. An increase in the electron speed will result in shorter-wavelength photons that are more penetrating. Conversely, a stream of slower-moving electrons will produce an x-ray beam consisting of longer-wavelength photons that are less penetrating. The factor on the control panel that adjusts the speed of the electrons is the kilovoltage (kV). When the numerical value is selected, it indicates the maximum kV, or kV peak (kVp), that will be applied to the cathode. This penetrability of the generated x-ray is considered the beam quality. For each density and thickness of material, there is an optimal kVp setting. For example, on a living patient, the optimal setting would be 55 kVp for a hand and 75 kVp for a lateral skull. Pathology that alters the density of tissue would necessitate compensation in the selection of kVp. For instance, a patient with osteoporosis, a condition that decreases bone density, might require a 5 to 10 kVp reduction to produce an image with acceptable penetration. For mummified remains, 55 kVp has proved to be most suitable for adequate penetration. When viewing a processed radiograph to determine if there is adequate penetration, looking “inside” the bone is considered the best area for an assessment of penetration. It should be possible to see “through” the bone and be able to discern structures such as trabeculae (Figure 2.1A). If it is not possible to see through the bone, the film is considered underpenetrated (Figure 2.1B). If it is possible to see through the bone but the cortex of the bone appeared gray instead of white, the film is considered overpenetrated

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Figure 2.1A  Lateral skull radiograph of the mummy known as George/Fred, taken at 55 kVp and 10 mAs. To assess the penetration, look at the teeth. Since it is possible to identify all the anatomical features, such as pulp canal, enamel, and dentine, the image is properly penetrated. To assess the density, look at the areas outside of the skull either in front of the teeth or behind the neck.

Figure 2.1B  The same projection, but taken at 40 kVp at 20 mAs. Because the mAs value was doubled from the previous exposure, it compensated for the decrease in the kVp, and the resulting films have the same density. However, since the anatomical features of the teeth are not discernable, the penetration at 40 kVp was insufficient and the image can be considered underpenetrated.

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Figure 2.1C  Another lateral projection, this time taken at 80 kVp at 5 mAs. Once again, the mAs value was adjusted to produce a density similar to the two previous images. The high kVp setting resulted in an image in which all the anatomical features appear as shades of gray and are not easily distinguishable. The image can be considered as overpenetrated.

(Figure 2.1C). Between the range of 55–80 kVp, the minimum change in kV to produce a noticeable difference in penetration is approximately 5 kV. Because the kV setting controls the penetrating ability of the x-ray beam, it also controls the visible contrast, the difference between black and white, on the image. Therefore, lower kVp settings are less penetrating and produce images that possess higher contrast: more “black and white” with fewer shades of grays. Conversely, higher kVp settings will generate more penetrating x-rays, resulting in lower-contrast images: more shades of gray and fewer areas of “white.” In addition to the quality (kVp) of the beam, there are variables that influence the quantity of x-rays produced. Manipulation of the quantity of x-rays is accomplished by manipulating two complementary factors, milliamperage and time. Milliamperage (mA) determines the quantity of electrons that will be available at the filament within the cathode. Time, usually in seconds (s), determines the duration of the exposure. Together, these factors combine to produce the milliamperage-seconds (mAs) and influence the overall “blackness,” or density, on the processed film. The region on the processed film to assess adequate density is the area around the part or object of interest. That area should be sufficiently “black” so that when the film is held up to the light, you can’t see your fingers placed about 10 in. (25 cm) behind the film. A film that lacks sufficient density, or “blackness,” is termed underexposed (Figure 2.2A). Conversely, if the film is too dense, it will obscure the part of interest and be termed overexposed (Figure 2.2B). In order to see a visible difference in density on a processed film, the mAs value either must be increased or decreased by a minimum of 50%.

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Figure 2.2A  A lateral projection of the skull taken at 55 kVp at 5 mAs. From the previous

image, Figure 2.1A, it was determined that the kVp selected provided sufficient penetration. However, because the soft tissue structure of the nose was clearly demonstrated and the area in front of the nose was “gray” and not “black,” the image must be considered underexposed.

Figure 2.2B  This lateral projection was taken at 55 kVp at 20 mAs. One again, the satisfactory kVp was selected; however, the mAs value is so high that the entire image is dark and should be considered overexposed.

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Shoulder

Density

Straight line

Toe

Exposure

Figure 2.3  The characteristic curve: graphical representation of the relationship between the intensity of the radiation exposure and the resulting density on the processed film.

The study of the relationship between the intensity of the radiation exposure and the resulting density, or blackness, on the film is known as sensitometry (Bushong 2008b). Although a thorough understanding of this complex topic is beyond the scope of this text, it will serve as a reference point later in the discussion of digital radiography. The graphical representation of sensitometry is known as a characteristic curve, or a Hurter and Driffield (H & D) curve (Figure 2.3). The graph is divided into three sections: the toe, straight line, and shoulder. Film exposures in the region of the toe would be considered grossly underexposed, whereas in the shoulder the effect would be extremely overexposed. The acceptable exposure would be in a narrow portion of the straight line region where smaller changes in mAs result in more noticeable differences in film density. The slope, or gradient, of the straight line section determines the film’s maximum contrast or latitude. A film with a steep slope would have inherently higher contrast, and as the slope decreases, there would be more latitude, lower contrast, and more shades of gray on the processed film. Focal Spot The area of the anode or target that is bombarded by the electron stream is known as the focal spot. The dimension of this area becomes significant when taking into consideration the interactions between the principal exposure factors, kVp and mAs. Only approximately 1% of the energy of the electron stream is converted to x-ray, and the remainder is lost as heat. The heat generated at the focal spot in the anode is directly related to three factors: the quantity (mA) of electrons available at the filament, the duration of the exposures, and speed of the electrons (kVp) applied to the filament. A fourth factor, the current waveform, is determined by the type of voltage fluctuation and may be identified simply as single phase, three phase, or high frequency. Single-phase current represents the greatest voltage fluctuation; it is the least efficient means of x-ray production and affects heat production the least, whereas high-frequency generation results in the least voltage variation and is the most efficient x-ray production during an exposure, but contributes significantly to anode heating.

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Since overheating of the anode reduces x-ray tube life, tremendous engineering efforts over the past century have been invested in designs to dissipate heat. The simplest and most basic design, the stationary anode supplied with single-phase current, was commonly found in dental and some portable units with lower kVp and mA outputs. These units generally had larger focal spots (1.0 mm/2.0 mm) and were the least expensive, but required longer exposure times to deliver the necessary amount of radiation. X-ray procedures that require very short exposure times necessitated equipment with high-frequency generators capable of higher kVp and mA settings and a smaller focal spot (0.5 mm/1.0 mm) embedded in a rotating anode to dissipate the tremendous heat produced. Most x-ray equipment found in hospital imaging centers, including modern portable units, is powered by high-frequency generators. In order to minimize damaging the x-ray tube, Manufacturers provide charts that indicates maximum kVp and mAs settings related to anode cooling times. The size of the focal spot ultimately determines the size of the object that can be visualized on the processed image. The smaller the focal spot, the sharper the image. Simply stated, a structure smaller than the focal spot size will not be clearly demonstrated. In medical imaging, mammography units have fractional or microfocal spots, less than 1 mm, typically 0.1 to 0.3 mm, to enable visualization of microcalcifications in the breast tissue. However, the smaller the focal spot size, the faster the anode will heat up. Therefore, focal spot size should be taken into consideration once the objectives of the study have been determined. Source-to-Image Distance The distance between the x-ray source and the image receptor also affects the exposure settings. Referred to technically by several terms such as the source-to-image receptor distance (SID), target-to-ἀlm distance (TFD), and focal ἀlm distance (FFD), this distance is based on the physical principle that x-ray photons diverge from the source of production. Because x-ray and visible light are both forms of electromagnetic (EM) radiation, the dispersal characteristics of both are identical and obey the inverse square law. If the SID is doubled, the intensity of the radiation would be reduced by 1/4. To compensate for the reduction of radiation, the quantity, or mAs, would have to be increased by a factor of 4. Therefore, the compensation procedure is known as the direct square law. For example, a satisfactory image is obtained using 10 mAs at a 100 cm SID. If the same object was radiographed at an SID of 200 cm, the quantity of radiation must be increased to 40 mAs to produce an image of satisfactory density. Image Distortion The appearance of the object on the image is affected by the SID and focal spot size (fss). Radiographs were originally known as shadowgrams or shadowgraphs because they resembled shadows cast by light. As previously mentioned, the dispersal rate of both forms of EM are identical and can therefore be demonstrated using visible light. To demonstrate this concept, position a light 40 in. (100 cm) from a wall. The wall represents the image receptor or the film. Place an object, for example your hand, 4 in. (10 cm) from the wall in the path of the light, and the shadow of your hand will be cast on the wall. Around the margin of the shadow is a “fuzzy” region known as the penumbra. As your hand moves closer to the wall, the shadow and the penumbra will reduce in size or be less magnified. If you move your hand further from the wall, the shadow and penumbra will get larger or more magnified. Therefore, in order to minimize magnification and penumbra, the object

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should be closest to the film, or more precisely, the object-to-image receptor distance (OID) should be as small as possible. However, unless the object is flat, the parts farther away from the film will be magnified more than those closest to the film. This unequal magnification is termed distortion. Parts of the object that are not in the same plane as the film will appear distorted on the processed image. Magnification and distortion are two related disadvantages of conventional radiography. Consequently, to minimize magnification and distortion, always place the part of interest closest and in the same plane as the film. If there are several parts of interest, additional exposures should be taken to ensure that each region or area of interest is closest and parallel to the film. Since it is extremely difficult to get all body parts, foreign bodies, and/or artifacts parallel to the film, it is fundamentally impossible to totally eliminate distortion. If the target structure of interest is successfully positioned parallel to the film, the actual size of the object can only be determined if the distance between the object and the film is known. Therefore, it is extremely difficult to determine the actual size of an object from a radiograph. Beam Collimation As previously indicated, x-rays diverge from the source at the same angle as visible light. A visible light source superimposed over the path of the x-ray beam and projected onto the subject will indicate the area of the subject that will be irradiated. When adjustable lead shutters are added to the visible light projection device, termed a collimator, it is possible to linearly shape the area that will be irradiated. There are three principal benefits to collimation. First, it greatly reduces scatter radiation, which degrades the image and reduces contrast. Second, it decreases radiation exposure to the patient and operator. Third, it allows the x-ray beam to be precisely centered and limits the area irradiated to only the area or part of interest.

Image Receptor: Film and Screens In 1895, the image receptors for photography included glass plates, flexible films, and papers coated with a light-sensitive emulsion. However, in Röntgen’s initial communication to the Würzburg Physical Medical Society, he stressed the importance of using photographic plates (Gagliardi 1996a). The plates were manufactured in “standardized” sizes, including 14 × 17, 11 × 14, 10 × 12, 8 × 10, and 5 × 7 in. Prior to being exposed, the lightsensitive plate was placed into a “light-tight” envelope. A 14 × 17 in. glass plate weighed approximately 2 lb (4.4 kg), was fragile and, because of its thickness, difficult to handle for direct viewing. Therefore, prior to interpretation, direct contact prints of the images were made on sensitized paper (Gagliardi 1996b). Radiography lexicon still contains an allusion to this original recording media: an anterior-posterior, supine projection of an abdomen is commonly referred to as a flat plate of the abdomen. A wrist x-ray on a glass plate in the early 1900s required a 30-min exposure. The long exposure was because less than 1% of the x-rays reaching the image receptor contributed to the formation of an image (Bushong 2008c). In February 1896, Michael Pupin, a Columbia University physicist, received a fluorescent screen from Thomas Edison. Since the screen, developed by Edison, fluoresced or converted x-ray to visible light, Pupin theorized he could reduce the exposure time by combining it with a photographic plate. He succeeded

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in producing the first intensifying screen-film image of a hand demonstrating the location of a shotgun pellet with an exposure of a few seconds (Eisenberg 1992b). By 1913 the high cost and other problems previously stated regarding the plates led to a search for a replacement film base. Because the finest glass specifically manufactured for x-ray exposure was produced in Belgium, World War I forced many nations, including the United States, to search for another substrate for the photographic emulsion. Cellulose nitrate was one of the first to be marketed with an emulsion coated on a single side. Because cellulose nitrate was flammable, it was soon replaced with cellulose acetate and today with polyester. Glass plates were still available at least until the mid-1980s for special applications (see Chapter 7, Figure 7.26). The photosensitive crystals in the emulsion were considered “ultra-fine grained” and the resulting images could be magnified many times. By eliminating the glass base, the thinner films had an emulsion that was more sensitive to x-rays and had a more conducive fit into a holder or cassette equipped with an intensifying screen. In 1918, Kodak introduced an x-ray film with an emulsion on both sides that could be placed into a cassette equipped with two screens. This new combination drastically reduced the exposure time and the radiation dose to the patient. In order to acquire a high-resolution image, nonscreen film was still used for some medical procedures, such as mammography, through the 1960s but single-emulsion nonscreen film was primarily relegated to industrial applications. Nonscreen film holders, often referred to as a cardboard holder, were commonly available through the early 1970s for mammography. However, by that time, a single high-resolution screen, single-emulsion film combination was developed for mammography. Although the single-emulsion film requires more radiation to achieve an acceptable image, it has one advantage over double-emulsion film: a less blurry and sharper image. Double-emulsion film, even though the film base is very thin at 150–300 µm (Bushong 2004a), provides two images separated by a very small distance. The result is a phenomenon known as parallax. When viewing objects a millimeter or less in size on doubleemulsion film, parallax results in apparent blurring of the object’s margins. For situations in which magnification is necessary, such as mammography, a single-emulsion film and single high-resolution screen is employed. Another benefit of a nonscreen approach is that the resulting image has increased latitude or more shades of gray. If the x-ray unit can produce the high mAs values required for nonscreen imaging, it will provide the best images (Figures 2.4A and 2.4B). In medical radiography, there has always been a trade-off between producing a diagnostic image and reducing the radiation exposure to the patient. To achieve this goal, films were developed with emulsions that were more sensitive to the light emitted by the intensifying screen. Similar to photography, one method to produce “faster” films was to increase the size of the light-sensitive crystals embedded in the emulsion. With an increase in crystal size, the exposure to the patient was decreased, but there was a corresponding decrease in detail or resolution on the processed film. A similar process occurred simultaneously in the development of intensifying screens. High-energy x-rays photons interact with the crystalline material in the fluorescent layer of the screen and are converted to many lower-energy photons of visible light. The larger the crystal embedded in the fluorescent layer, the more light photons generated from a single photon of x-ray. A high-speed screen would be very efficient at converting x-ray to light, but at the cost of a loss of detail. However, another consequence of using intensifying screens is an increase in contrast over nonscreen images. Without screens, the image is produced

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Figure 2.4A  An anterior-posterior, or AP, projection of the abdomen of an Egyptian mummy from the library at Cazenovia, New York, taken with a screen cassette. Note the high-contrast appearance, black and white with few shades of gray, of the image. An organ packet can be easily seen in the abdomen (arrow). Below the packet, the entire area appears as a “black” void.

solely by the differential absorption of x-rays. The visible light emitted from the screen eliminates some of the subtle differences in density that produce the shades of gray on the processed film. The result is fewer shades of gray and more black and white. Screens are rated according to their ability to convert x-rays to visible light. A slow speed screen may be assigned a value of 100. For the sake of simplicity, let’s say it will convert one photon of x-ray to 100 photons of light. This means that the original exposure variables (mAs) without screens can be reduced to 1/100 of the mAs with the intensifying screens. A par speed screen would be rated at approximately 200, a high-speed screen at 400, and an ultrahigh-speed screen at 1200. Shorter exposure times have two advantages: they reduce the radiation dose to the patient and eliminate involuntary movement, which would blur the image. A high-speed film/screen system would be an excellent choice for a chest radiograph when it is important to reduce the exposure time to minimize the effect of heart motion. However, the high-speed system would render very little trabecular detail within the long bones. Orthopedic radiography, on the other hand, would use the slower-speed screens to produce bone images with more detail. Therefore, for optimal results, film and screens of similar speeds would be matched for specific imaging objectives. If film and screens are not matched, the exposure (mAs) required may need to be adjusted and the resulting shades of gray, or latitude, available on the processed image may be compromised. There are also specialty cassettes for specific applications. Standard x-ray film comes in a 14 × 36 in. (35.5 × 91.4 cm) size and is typically used in orthopedic or chiropractic medicine to image an entire spine. This film size requires a special cassette. These specialized

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Paleoimaging: Field Applications for Cultural Remains and Artifacts

Figure 2.4B  The same region radiographed with a nonscreen film holder. Since an intensifying screen was not used, the film had lower contrast with many shades of gray visible. As in the previous image, the abdominal packet was seen; however, soft tissue structures were noted where there was only a “black” void with the screen image.

screens are also available with varied degrees of intensification, with one end of the cassette being faster than the other. Xeroradiography, or dry radiography, was a type of radiographic technique in which the image of the body was not recorded on film but on paper, eliminating the need for wet film developers (Selman 1985). In this technique, a plate of selenium, resting on a thin layer of aluminum oxide, was charged uniformly by passing it in front of a screen-controlled corona device termed a scorotron. As x-ray photons interacted with this amorphous coat of selenium, charges diffused out, in proportion to energy content of the x-ray. This process was a result of photoconduction. The resulting imprint, in the form of charge distribution on the plate, attracted toner particles, which were then transferred to reusable paper plates. By the late 1970s, xeroradiography became an alternative to using film for mammography. There were a number of advantages over the film, including lower patient dose than with nonscreen film mammography, a dry chemical process, margins of varying density materials were enhanced, and wider latitude that demonstrated more materials with similar densities (Gagliardi 1996c). In addition, because it was printed on paper, a view box was not needed to view the image. In 1977, a French team used xeroradiography to obtain a lateral image of Ramses II’s skull. The image revealed that the embalmer packed the pharaoh’s nasal cavity with peppercorns and employed a small bone to support the tip of the nose (Lang and Middleton 1997). By 1990, xeromammography was replaced by a

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single-screen film system that provided better images at even lower patient doses (Bushong 2004b). Subsequently, Xerox stopped making the toner required for the processes, and xeroradiography became another footnote in imaging history. In the past decade or so, shortening the length of time it takes to complete the patient’s examination has also become a consideration. The more patients examined in an hour, the higher the profits to the imaging center. This concept, termed throughput, has been a factor in the development of new hardware and software, and will be discussed in more detail in Chapter 3. Since the emulsion slowly deteriorates over time, medical imaging film has an expiration date, and medical facilities cannot use outdated film on patients. This expired film can be a tremendous resource for field forensic or anthropological research projects. Outdated film can be obtained either from medical facilities or vendors; however, there will likely be a mismatch between the film and light frequency emitted by the screens. Several test exposures will be necessary to formulate a technique chart for the optimal mAs settings.

Darkroom: Film Processing Since radiographic film is sensitive to light, a light-tight enclosure is necessary to load cassettes and process the film. The first requirement has always been less complex than the latter. A formal darkroom is described as a room that is light tight, has the appropriate chemistry available for film processing, and has a source of fresh water. Until about the early 1960s, most exposed x-rays were processed manually. Tanks were required for developer, water, and fixer. In addition, copious quantities of running water were necessary to wash the fixer from the processed film prior to drying. Not to get too technical, the function of the developer is to serve as a reducing agent, donating electrons to the exposed silver ions in the film emulsion and thus converting them to black, metallic silver. Each sheet of x-ray film consumes a certain amount of donated electrons and eventually exhausts the developer. To compensate for exhausted developer, a concentrated developer termed replenisher is periodically added to the tank. In addition, because the developer is a reducing agent, it is very susceptible to oxidation and can be inactivated if exposed to air for long periods of time. The action of the developer is temperature dependent. At 68°F (20°C), development, with agitation of the exposed film, should be 5 min. Combined with the time for fixing, washing, and drying, the entire process could take 30 min before a processed, dried image could be examined. The term wet reading found its way into the lexicon to indicate a film that was viewed by the radiologist prior to having completed the drying process. Under normal circumstances this long period was acceptable; however, in emergency trauma or operating room cases it was unacceptable. In 1951, a Polaroid system was introduced to eliminate the need to wet process film (Robbins and Land 1951). The system that provided an “instant” image within 90 s became obsolete with the advent of automated or automatic processors and ended Polaroid’s intervention in the medical imaging market. By today’s standards, the early processors were massive, but a dry image was available in about 5 min. Today, processors are manufactured for low-volume operations that can fit onto a darkroom countertop and take about 2 min to produce a dry film. To achieve the shortened developing time, the processor runs at about 95°F. Since film development is

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a temperature-dependent process, fluctuations even as little as 5° higher or lower may result in an over- or underdeveloped image. In addition to the temperature, automatic processors also maintain the concentration of the developer by introducing a specific volume of replenisher each time a film is introduced into the unit. The specific design of automatic processors is partially based on the expected volume of films that will be processed in a day. Although automatic processing is available in many locations, aspects of image production such as daily volume, replenishment, and temperature regulation are major reasons for production of an unacceptable image. Clearly, the challenge of regulating these variables is amplified in the field imaging setting.

Field Radiography Applications: Considerations and Challenges General Considerations Field radiography may be defined as a radiographic examination outside of an established imaging center. Contextual examples for field radiography include remote research facilities, tombs, caves, and museums. Considerations regarding field radiography instrumentation and technique are determined by two primary factors: the proposed location of the study and the specific research goals. Each of these factors in turn produces a wide variety of additional considerations to be addressed while planning the field-imaging project. The first step in any research project is to define the objectives, and this is no different for a field-imaging study. If the objective of the project is to complete an imaging triage study of a group of mummies in a remote location outside the United States, the preparation will certainly be different than if the remains are housed in a nearby museum. When determining which instrumentation to employ and what type and quantity of image receptors to use, the paleoimager must consider such variables as the following: 1. How many mummies and/or skeletons are associated with the project? 2. What will be the minimum projections required? 3. What is the predominant cultural practice with regard to mummification position, extended or flexed? 4. What is the nature of the travel required by the project? 5. How can the necessary equipment and supplies be kept to a manageable weight yet include everything that might be required? 6. What problems may be encountered when trying to transport x-ray film, since film packed in checked baggage will be subject to security x-ray inspection? 7. What are the issues surrounding the customs requirements for entering foreign countries and returning your equipment back into your country of origin? 8. Is a list describing the equipment and their serial numbers necessary? 9. Is a list of equipment all that will be needed or is additional official documentation required? It is apparent that many considerations need to be taken into account in field radiography projects. These and other factors are addressed in the following sections.

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Field Imaging: Specific Considerations The Radiographic Unit Although selecting an x-ray unit may be based on what you can get as dictated by budget or donation, it cannot be stressed enough that the equipment needs to be operated by a trained radiographer with paleoimaging experience. After providing some training, on occasion the authors left equipment with researchers in the field, only to find that they did not anticipate the impact of their application on the unit itself. In one instance, while attempting a long exposure, the unit overheated and the filament broke, rendering the unit inoperable. Without proper knowledge of exposure settings, positioning, and safe unit operation, the results can be disastrous. There are several ways in which the tube can be cooled, but the key is in knowing how to achieve the imaging objectives without damaging the equipment. A variety of challenges to conducting field radiographic work arise when planning and executing such expeditions. The instrumentation not only has to be compact and light enough to be transported, but also flexible enough to be able to adapt to any number of possible application situations. Dependability of the selected unit is critical. Many of the field challenges described in this chapter are applicable to conventional radiography applications in imaging centers as well, particularly in the forensic setting. Although the authors do not object to radiographic studies of mummified remains being conducted at imaging centers, we feel it is imperative that initial radiographs be conducted on site to determine if the mummy can be moved and if the preliminary data suggest that transportation and its inherent risks are warranted. A new high-frequency-generated portable x-ray unit would certainly be the simplest approach to an x-ray source. At a cost of approximately $12,000, a MinXray HF 100/30 veterinary unit comes equipped with a collimator and laser-centering light. In addition, it is packed into a nearly indestructible transport case, and together they weigh less than 50 lb (23 kg). However, older operational x-ray units abound. Most, such as dental and mobile x-ray units, are low output, generally not greater than 15 mA and 80 kVp. Since mummified and skeletal remains only require 55 kVp and, due to the lack of motion, long exposure times are not a problem, these units certainly meet the needs of anthropological and archaeological research. Older dental, medical, and veterinary portable units can usually be disassembled into two separate components, a control unit and an x-ray tube. These nonmounted components can be easily packed for transport and then reconfigured on-site to meet the imaging needs of the particular project. Often, project directors in locations where there are large stores of mummified remains desire a permanently mounted radiographic unit at the research site. In some of these situations, a mounted x-ray tube is put in place. Unfortunately, a permanently mounted x-ray tube loses the flexibility of application needed. A fixed x-ray tube requires that the subject be brought to the unit and, frequently, the ability to angle the tube is sacrificed. Tube angulation is often necessary to place a body part parallel to the film. The preferred approach is to use a nonpermanently mounted system. This method allows the tube to be placed and directed as the case dictates. The nonmounted system permits unlimited angling, and therefore provides views that have greater interpretability. Additionally, the nonmounted system reduces or eliminates the need to move the subject to the unit, thereby permitting radiographic examination in virtually any remote location, such as within a tomb or a cave.

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Paleoimaging: Field Applications for Cultural Remains and Artifacts

One particular unit that has been a real workhorse for our paleoimaging team is a 1952 Picker Field Army Unit that was originally used in the Korean conflict and is designed for rugged environments. The unit has two functional pieces and requires two carrying/ shipping cases, creating the need to add baggage-handling costs to each project. Another drawback is that it weighed over 80 lb! We now use a much lighter single-piece unit, the previously mentioned MinXray HF 100/30 veterinary unit. Utilities When using radiography in the field, electrical requirements for the equipment must be considered. Often, in remote regions there is no electricity. In other areas there may be electricity, but at best only fluctuating output during certain hours of the day, depending on factors such as the time of year and reservoir water levels required for power generation. We recall one unique power situation in Tucame, Peru, in which our power requirements were such that when we activated the radiographic equipment, the nearby town would experience a transient “brown out”! Although electric power may be available, it may be a different voltage than required by the radiographic instrumentation. With these and other unexpected situations related to available power, researchers need to learn as much as they can about the available power and remain flexible with their protocols. In cases where there is no power available, a gasoline- or diesel-powered 5000 W generator is the best option. When relying on a generator, it is important to estimate the potential usage and determine the additional fuel needs for the generator itself. These units are quite heavy and may require transportation into remote regions where no vehicle can travel. This can be accomplished either by carrying the generator or by fashioning a travois, which may be hauled by a beast of burden. In either case, additional manpower will be required for this task. In the case of travois transport, a mule wrangler may be needed as well. The generator is also useful as a backup power source in those regions where the electric power is only active during certain hours of the day. In most countries, electricity is supplied at 220 V at 50 Hz (hertz or cycles per second). Equipment manufactured in the United States is designed for 110 V at 60 Hz. In order to use the lower voltage units outside the United States, an electrical transformer is required to adjust the current. Traveling with a transformer can be challenging, as it tends to add considerable weight to the overall equipment being transported. Newer transformers are available that are much lighter and, therefore, more practical. Another important “utility” to consider is water. The availability of water for film processing is critical, as it is required to rinse conventional x-ray film once processed. Access to an ample water supply may be a challenge or, in some cases, the use of the local water may even reduce drinkable water supplies. Additionally, the particulate and mineral content in some local water may impact the final image when processing conventional film. The pH of water with a high mineral content may affect the chemistry used in manual processing. Since the fixer is acidic, the higher pH of the water will tend to neutralize the fixer and require more frequent replenishment of the chemical. In one remote location in the Osmore River Valley near Ilo, Peru, in an effort to conserve water and to create water that was free from minerals, we proposed and designed a water distillation system.

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X-Ray Tube Support System The x-ray tube will often require some mechanism by which the tube is suspended over or placed under the subject of study. The decision of where to place the x-ray tube should depend on a combination of concern for the fragility of the subject and, often more importantly, convenience. Although commercial support systems are available, they may weigh as much as a 100 lb (45 kg), adding extra unnecessary weight. Designing supports for the x-ray tube is a creative process; they can be a formal arrangement of specific metal tubes or an informal contraption that is made from whatever you have available to you. A formal x-ray tube support system can be constructed from a series of aluminum electromechanical tubes (EMT) cut into 20 in. (50 cm) sections. Once the EMT system has been constructed, the x-ray tube can be secured to the support with duct tape or another suitable clamping system (Figure 2.5). This formal EMT system has the advantage of being flexible in its possible configurations and is quite sturdy, which is important with some of the heavier x-ray tubes. The major disadvantage is that the system, even when dismantled, is heavy and cumbersome, making transportation a greater challenge. Additionally, the set-screws in the hardware used to join the EMT sections can strip, requiring spare parts to be included with the supplies transported to the site. Informal x-ray tube support systems can be fashioned with common items such as sawhorses, wooden posts, construction rebar, rocks, equipment cases, stacked chairs, and ladders found at the research location (Figures 2.6A and 2.6B). Instead of positioning the

Figure 2.5  The electromechanical tubing (EMT) frame supporting the x-ray tube (arrow).

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Paleoimaging: Field Applications for Cultural Remains and Artifacts

Figure 2.6A  The x-ray tube fastened to the pole with duct tape.

x-ray tube for anterior-posterior projections above the remains, the radiation source can be placed on the floor with the beam directed up for posterior-anterior projections (Figure 2.7). Since duct tape always seems to play a major role in the design of these informal x-ray tube support systems, sufficient quantities should be included with supplies.

Figure 2.6B  X-ray tube placed on stacked chairs for a lateral projection of a mummy.

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Figure 2.7  X-ray tube placed on the floor to project the x-ray beam vertically through the skull of the mummy called James Penn. The EMT frame was used to support the film holder.

Image Receptors As described earlier in this chapter, image receptors come in a variety of shapes and sizes, and have set technical factors. Discarded cassettes can be easily found at medical centers or imaging equipment vendors. Optimally, a 14 × 17 in. (35.5 × 43 cm), 100-speed screen would be the best all-purpose choice. This size would cover a large area of the mummy or artifact, and if disarticulated skeletal remains are the study subjects, a number of bones will fit onto a single film. A 14 × 36 in. (35.5 × 91.4 cm) cassette would be a great find. Although that size film has become more difficult to locate (trifold versus single sheet), the greater challenge is loading it into the hanger for manual processing. The cassette can be loaded with two sheets of standard 14 × 17 in. (35.5 × 43 cm) film with 2 in. of screen uncovered (Figure 2.8). The primary advantage of the long cassette is that it covers a large area of the mummy in a single exposure. The principal disadvantage is that generally an SID of 72 in. (190.5 cm) is necessary for the radiation to cover the entire 14 × 36 in. (35.5 × 91.4 cm) cassette. Conventional radiographic film/screen imaging systems can be problematic. Although expired film can be easily obtained, it may be difficult to match the speeds of the donated screens with expired film. The main disadvantage of a mismatched system is a change in the relative speed and, possibly, a loss of detail. However, if the film and the screen were donated, the financial savings are certainly worth the loss of a little detail and contrast. When detail is necessary, such as an infant bundle, a nonscreen film holder should be used instead of the cassette equipped with intensifying screen. The resulting image will have greater detail and the textile wrappings and some soft tissue structures may be more clearly visualized (Figures 2.9A and 2.9B). If a nonscreen film holder cannot be located, one can easily be fashioned using the black plastic liner found in boxes of many brands of

40

Paleoimaging: Field Applications for Cultural Remains and Artifacts

Figure 2.8  Two 14 × 17 in. (35.5 × 43 cm) films placed into a 14 × 36 in. (35.5 × 91.4 cm) cassette. Note there were 2 in. (5 cm) on the right side of the cassette, where there is no film.

x-ray film (Figure 2.10). If the black bag liner is not available, one can be easily constructed. Cardboard or 1/8 in. (3.1 mm) Foamcore® can be used as a “stiff” base. The base is then placed into an “envelope” made of black swimming pool liner. The simple black bag film holder without the cardboard or foamcore has the advantage of being more flexible. Using film without a cassette or screen has various applications. If the space behind the subject is too narrow to allow the passage of a cassette or there is no way to support the cassette behind the subject, nonscreened film can be slid into that space (Figure 2.11). The flexibility and lightweight nature of a nonscreen film holder can be utilized for projections, such as a lateral skull, that could not have been taken without a more complex, timeconsuming approach (Figures 2.12A and 2.12B). Another application is when the goal is to image a very large area at one time. Using nonscreened film and allowing the film to overlap so that the images may be reconstructed during postprocessing will produce a single image of the large subject. The drawback to the nonscreened method is that the exposure time needs to be increased by a factor of 100. If a single long exposure were taken, the x-ray tube would overheat and result in permanent damage. Many shorter exposures must be

Figure 2.9A  An AP (anterior-posterior) projection of the pelvis and legs of a Guanajuato infant mummy (M1M3) taken with a Polaroid screen cassette at 46 kVp and 1.2 mAs.

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Figure 2.9 B  A similar projection of another Guanajuato infant mummy (GMO8), taken with-

out the use of a screen, on Polaroid film at 46 kVp and 150 mAs. Note the more defined appearance of the trabecular pattern in the right ilium with the nonscreen image. In addition, the film taken without the use of the screen provides visualization of the soft tissue structures of the legs.

taken to avoid the overheating potential, and additional care must be taken to keep the x-ray tube cool. The authors have used ice, cool packs, and in one case, chilled champagne to keep the tube cool (Figure 2.13). Another image receptor system that was available, instant film, will be discussed following the description of film changing and processing challenges. The instant film eliminated many of these challenges, thereby streamlining the conventional imaging procedure.

Figure 2.10  An old commercially available nonscreen film holder on the right and the black plastic envelope removed from a box of film on the left. The latter can be used as a nonscreen film holder.

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Paleoimaging: Field Applications for Cultural Remains and Artifacts

Figure 2.11  Since the mummies were fastened to the wall, it was not possible to place a conventional cassette behind the mummy. Here, a Polaroid film packet was easily placed behind the thorax of a mummy (U1) in Urbania, Italy.

Darkrooms The major disadvantage of conventional film is that it is light sensitive, and cassettes must be loaded and unloaded in a light-tight place. We describe the use of both informal and formal darkrooms, as well as portable darkroom construction at the field site. An informal darkroom or film-changing space can be created in a very short time at the location of the imaging study. A room, such as a bathroom or even a closet, can often be easily rendered light tight (Figure 2.14). Black gardening plastic or black pool liner held

A

B

Figure 2.12A  Positioning for a lateral projection of the skull of a mummy in Urbania, Italy. The nonscreen film holder (A) was held in place by the tape. The x-ray tube (B) was placed on a pile of boxes for the exposure.

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Figure 2.12B  The resulting Polaroid image of the standing mummy in Urbania, Italy. Note the extreme wear on the maxillary molar (arrow).

in place by duct tape will eliminate light from windows and around doors with particular attention given to door jambs (Figure 2.15). More inventive light-tight film changing spaces were created within museum displays, a circular staircase leading from a museum up into a cemetery, bathroom stalls, and a church confessional (Figure 2.16). Exposed films can be stored in a light-tight transfer case (BarRay®) that resembles a briefcase. These containers can easily hold about 100 exposed films and can be transported to an automatic processor in a formal darkroom. Formal darkrooms may be located at medical facilities, universities, and chiropractic, podiatric, and veterinary practices. Many of these facilities have automatic film processors within their darkrooms. Since processing images of remains will not have precedence over patient or client images, using established automatic, or even manual processing facilities,

Figure 2.13  Cold packs taped the either side of the x-ray tube to cool the unit during multiple

exposures.

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Paleoimaging: Field Applications for Cultural Remains and Artifacts

Figure 2.14  An example of a “native hut” in a museum in Iquique, Chile, that was turned into a darkroom to load and unload cassettes. In order to make the space light tight, the inside of the window (arrow) of the hut was covered with black plastic and a door was fashioned with black felt. Incidentally, the felt, acquired from a local fabric shop, had a Christmas tree and star pattern that was fluorescent. However, the wavelength of the light given off by the fabric did not fog the x-ray film.

Figure 2.15  Black plastic used to cover the window in a bathroom.

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Figure 2.16  Material (arrow) placed over the door of a confessional in a church in Moquegua, Peru, to convert it into a light-tight film changing “room.”

must be scheduled for a specific time of day. Depending on the volume of films processed per day, the quality of the developing chemistry can change during a particular day or after a certain number of films has been processed. Therefore, large numbers of films processed at once, commonly termed batch processing, can be problematic. First, test exposures should be taken bracketing the exposure setting, meaning that an exposure should be made with what would be the expected mAs. Next, a second exposure is taken with half the mAs and then a third exposure with double the mAs. All three images are processed at the time of day that the batch processing would take place. From the processed images, the best exposure setting is noted, and that becomes the mAs that will be used in the field imaging project. Usually, the processing facility is a minimum of several miles or kilometers from where the study is taking place, and trips to process the films can be very time consuming. Even if the technical factors result in an acceptable image, a film may need to be repeated due to poor positioning or an inadequate demonstration of a particular anatomical or pathological feature. Repeat imaging drastically slows down the progress of the study and may severely limit the number of specimens examined. If there is no place to create an informal darkroom, and no formal darkroom is available, a portable darkroom can be constructed. Although there are commercially available portable darkrooms, they are typically designed for standard photography and are too small for the needs of x-ray film processing. A portable darkroom can be constructed using precut PVC pipe with the appropriate connectors as the framework (Figure 2.17). An 8 × 3 ft (2.4 × 0.9 m) length of black felt is first draped over the front to act as the first layer of the

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Paleoimaging: Field Applications for Cultural Remains and Artifacts

Figure 2.17  The PVC pipe frame for the portable darkroom.

door (Figure 2.18). A second layer of black felt is laid over the first layer to create a double door to ensure a light-tight opening. The entire frame is then covered with light-tight material and secured in place with clamps (Figure 2.19). If it is designed well, there is room for extra film and the three necessary processing tanks. The authors have used this darkroom

Figure 2.18  Two layers of felt are used to create a light-trap door.

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Figure 2.19  The entire PVC pipe frame covered with two layers of black plastic at right angles to each other.

successfully on such remote locations as on a rooftop and adjacent to a Buddhist temple. If you really want to get fancy, an entry fly can be affixed to the door end to provide shade (Figure 2.20). Film processing, too, must be considered. If only eight to ten 14 × 17 in. (35.5 × 43 cm) films are going to be processed per day, three large plastic photographic trays would suffice for the chemistry. If more than ten films per day are going to be processed, a conventional manual x-ray film processing workspace must be constructed. The easiest method would

Figure 2.20  The portable darkroom was covered with a “space blanket” to provide a reflective surface and a tent fly to shield the entrance.

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Paleoimaging: Field Applications for Cultural Remains and Artifacts

be to acquire a stainless steel tank system designed for this purpose. Until recently, small chiropractic, podiatric, and veterinary practices manually processed their x-rays. Once they converted to automatic processing, their used wet processing tanks were discarded. These units may be available from local radiographic equipment dealers. Generally, these units consist of two 5-gal tanks, one for developer and the other for fixer, that sit within a much larger, approximately 20-gal tank that would be filled with water. The water tank served several purposes. It was used to wash the film after development and fixing, and it also maintained the temperature of the chemistry. The large tank usually was directly connected to the water supply so that a continuous flow would eliminate contaminated water and also wash the fixer from the film before it went to the dryer. Since the water/wash tank is so large, it is not practical to transport to a field facility, particularly if it is outside the continental United States. A more appropriate approach would be to acquire three 5-gal stainless steel tanks, one each for developer, fixer, and water. The latter would only be used as a wash between the developer and fixer. As a cautionary note, many of the 5-gal tanks have a cork located on the bottom of the tank to permit drainage. When submerged in the larger tank, the cork does not present a problem. However, if the tanks are used independently, they must be placed on a rack with thickness equal to the thickness of the cork or they will be unstable. Another option is to construct three tanks out of marine plywood. The wooden containers are nearly indestructible and would also serve as sturdy transport boxes to bring material to the site. To transform the plywood boxes into watertight tanks, the authors fabricated a liner from heat-sealed vinyl roofing material (Figures  2.21A and 2.21B). A fiberglass liner would also serve the same purpose. The three processing tanks need to have lids to avoid evaporation, which would cause a change in the chemical concentrations. It is important to place the tanks in order of use in the developing process and to secure the tanks to avoid knocking them over in the dark (Figure 2.22).

Figure 2.21A  Vinyl roofing material heat-sealed to create a liner for plywood tanks.

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Figure 2.21B  The vinyl liners within plywood processing tanks. A PVC pipe (arrow) was placed on the faucet to permit better flow into the wash tank.

A final wash tank would have to be devised on site. The easiest approach would be to use a 30-gal plastic container with a hose to provide continuous water flow (Figure 2.23). If an electrical power supply is available, a circulating water pump can be placed into the container to move the water within the tank. Film Drying and Viewing Film drying is a pretty straightforward and logical procedure. Simply string a clothesline either inside or outside the building, and hang the film on it with clothespins. Drying inside the building has the advantage of minimizing debris attachment to the wet surface before the films are completely dry. It can also be done regardless of the weather. Film viewing in the field is usually accomplished “al fresco.” Simply hold the film up to the sun or a bright light and begin interpreting the data.

Figure 2.22  Plywood tanks positioned within the portable darkroom.

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Paleoimaging: Field Applications for Cultural Remains and Artifacts

C

B

A

Figure 2.23  A 30-gal container (A) that was used as a wash tank in Leymebamba, Peru. Note the film hangers (B) resting on the post, the lead apron (C) hanging on the post, and the x-films drying on the clothesline.

Instant Film At this point it should be clear that conventional film has a number of disadvantages in a field application. Even though large quantities of film may be easily acquired as a donation, the need for a darkroom, chemistry, and water make it tremendously problematic. In addition, even if automatic processing is available, the occasional need to repeat films will result in the examination of fewer specimens. Because x-ray and visible light are both forms of electromagnetic radiation, photographic films and papers used for photographic prints can be used to record radiographic images. Since Polaroid provided a solution for medical imaging over 50 years ago, it seemed the logical choice. Through the mid-1980s, old Polaroid medical imaging systems could be found in storage at many major medical centers. In a 1986 study of a mummy known as the “Soap Lady” at the College of Physicians Mütter Museum in Philadelphia, Pennsylvania, the Polaroid system made it possible to complete a radiographic examination of the mummy on-site (Conlogue et al. 1989). Although several medical imaging centers were within a few miles of the museum, the mummy was too fragile to be transported. A donated 30-year-old x-ray unit was brought to the site for the study, but processing the images would have to be done at a medical center. Since the relative speed of Polaroid intensifying screens matched the speed of the conventional radiographic screen cassette, the exposure factors for different regions of the

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Figure 2.24  The 4 × 5 in. (10 × 12.7 cm) Polaroid Type 53 film of a femoral head and neck. Note the detail resolution of the trabecular pattern.

body were established with the Polaroid system. Using the Polaroid technical factors, over a dozen conventional 14 × 17 in. (35.5 × 43 cm) radiographs were obtained without having to repeat any exposures. Unfortunately, Polaroid discontinued the manufacturing of the film for its imaging system in 1990. In 1997, once again the need for a nonconventional radiographic film recording media was necessary for the establishment of a field radiographic facility at an anthropological site in Peru (Conlogue and Nelson 1999). Polaroid Type 53 photographic film provided a partial solution to the problem. Since it was a film intended for photographic applications, it could not be used with an intensifying screen, but only as a nonscreen image receptor. The two major disadvantages were that nonscreen imaging required extremely long exposures, often many seconds long and the limited size of the 4 × 5 in. (10 × 12.5 cm) film. However, the film was large enough to image small structures, such as a femoral head to determine trabecular patterns in age determination (Figure 2.24) or mandibles to access dental development and pathology (Figure 2.25). Although it did not completely eliminate the need for conventional radiographic film, it did reduce the number of films that needed to be processed and established the value of Polaroid in the field. A representative (Phalen 1998, personal communication) for a Polaroid distributor suggested a larger-format (8 × 10 in. [20.3 × 25.4 cm]) product that could be used with an intensifying screen system introduced in 1984 and manufactured by Calumet Photography. The system, targeted for use by veterinarians, podiatrists, and bomb squad personnel, also had two types of film available. Because the films were photographic products, the film sensitivity was indicated in ISO (International Organization for Standardization) and the European equivalent DIN (Deutsche Industrie Norm) units (Redsicker 2001). The faster the film, the higher the ISO/DIN. Unlike x-ray film, which is orthochromatic, that is, sensitive to only specific wavelengths of light, photographic film is panchromatic and therefore reacts to the entire spectrum of visible light. Type 804, Polapan Pro 100, was the slower, more detailed film (100 ISO) described as a glossy finish, medium contrast with a key application identified as professional photography proofing (Polaroid, a). Type 803 (800 ISO)

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Paleoimaging: Field Applications for Cultural Remains and Artifacts

Figure 2.25  Three views of an infant mandible on 4 × 5 in. (10 × 12.7 cm) Polaroid Type 53

film.

was described as a high-speed, glossy finish, medium contrast with a broader range of key applications including microscopic imaging, copy stand photography, and x-ray bomb detection (Polaroid, b). The authors have used both the Type 804 and the Type 803 in field imaging settings with excellent results. It is important to realize the differences in the application of the two Polaroid Type films. The slower speed, Type 804, loaded into the cassette provided excellent detail. Since Type 803 is more sensitive, it was better suited for situations when there wasn’t sufficient space for the cassette and the nonscreen approach was necessary. For example, if the technique required for a Type 804 film loaded into the cassette required a 2 s exposure, that same film would need 200 s for the same nonscreen exposure. However, because the Type 803 requires 1/8 the exposure time as the Type 804, only a 25 s exposure would be necessary. Not only is less time required to produce the image, but also the reduced exposure time has the additional advantage of prolonging the life of the x-ray tube. In a laboratory situation, an object or specimen similar to that which will be encountered in the field can be used to determine the optimal exposure factors for the Polaroid and conventional radiographic film/screen systems. A conversion factor can then be calculated. Once in the field, the appropriate technique can be determined with the Polaroid system, the conversion factor applied, and a series of conventional films can be taken with the adjusted technique. At the end of the day, the exposed films can be transported to a facility for batch processing, saving valuable on-site research time.

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There were three drawbacks to using Polaroid film as a field image receptor: limited size (4 × 6 or 8 × 10 in.; 10 × 15.2 or 20.3 × 25.4 cm), cost (about $15.00 per sheet for the larger size), and the need to ship it to the country where the study was to be conducted. The cost made it prohibitive for large-scale projects. Even with those considerations, the instant film yielded excellent detail and eliminated the need for a darkroom and wet processing chemistry. The ideal system for fieldwork would be a filmless digital x-ray system, which will be discussed in Chapter 3. However, recently an even greater disadvantage materialized. As of May 2008, Polaroid stopped manufacturing Type 804 and 803 films. The experience with the Polaroid suggested that other photographic products may also provide satisfactory images. In order to eliminate the problems associated with shipping materials outside of the United States, a photographic product that would be available universally was sought. It was decided to test Ilford MGIV photographic print paper. As a photographic product, it was sensitive to a panchromatic spectrum of light similar to the Polaroid photographic products. As a comparison, one sheet of the 8 × 10 in. (20 × 24.5 cm) Ilford paper was loaded into the Polaroid cassette, and another sheet loaded into a 100speed conventional radiographic cassette. Following each exposures, the paper was placed into a cylindrical Unicolor eight real day light processor (Figures 2.26A and 2.26B) and developed with Ilford PQ Universal developer with agitation of 30 s. The developer was drained and fixer poured into the tank and agitated for another minute. After the fixer was poured off, the paper was washed in the tank for 5 min. The resulting images demonstrated that the Ilford paper placed into the Polaroid cassette provided an excellent image (Figure  2.27A). However, because the conventional radiographic screen emitted orthochromatic light, the resulting image with the Ilford paper in the x-ray film holder was unsatisfactory (Figure 2.27B). An additional test was carried out with the Ilford paper in a nonscreen film holder (Figure 2.28) with excellent results (Figure 2.29). It certainly would be impractical to carry out an entire study using the photographic print paper; however, the paper has several applications. Once the satisfactory kVp and mAs, have been established for the photographic paper, a conversion factor for conventional radiographic film can be calculated. This reflects the procedure described previously for the 1986 study of the Soap Lady. In addition, “on-the-spot” images can be obtained to check positioning before conventional radiographs are taken. If the positions need to be altered, it can be done without the delay of having to wait for the conventional radiographs to be processed.

Figure 2.26A  Unicolor ® day light processor.

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Paleoimaging: Field Applications for Cultural Remains and Artifacts

Figure 2.26B  Photograph showing the orientation of the Ilford photographic paper (arrow) within the Unicolor ® tank.

Figure 2.27A  Lateral skull radiograph using Ilford photographic paper loaded into a Polaroid

cassette.

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Figure 2.27B  Lateral skull radiograph using Ilford photographic paper loaded into a cassette with conventional radiographic intensifying screens.

Figure 2.28  Positioning the Ilford paper in a nonscreen film holder.

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Paleoimaging: Field Applications for Cultural Remains and Artifacts

Figure 2.29  Lateral skull radiograph with Ilford paper loaded into a nonscreen film holder.

Positioning Even if the most sophisticated facilities are available, poor positioning of the remains will render the images of little value. Proper positioning can minimize the effects of superimposition of shadows, one of the principal disadvantages of conventional radiography. Wrapped mummified remains present the greatest challenge, particularly if they are in a flexed position. Without the ability to visually identify landmarks, the first image only documents the relative position of internal structures. From that x-ray, a skilled radiographer should be able to determine how to manipulate the mummy bundle to achieve the required position. Even if the remains are in an extended position, subtle manipulation of the remains may be required. For example, if a suspected structure, such as a fracture, is noted on a projection (Figure 2.30A), the body can be rotated into an imaging perspective that will more clearly visualize the region in question (Figure  2.30B). In situations where the remains cannot be safely rotated, the x-ray tube and the image receptor can be positioned to achieve the same results (Figures 2.31A, 2.31B, and 2.31C). For skeletal material, the task is less formidable. Since the bones can be placed directly onto the image receptor, there should be no questions as to the position. For both the mummified and skeletal remains, imaging projections should be identical to those used in medical imaging. There are volumes dedicated to describing proper position methods (Frank and Ballinger 2003) for the entire body, and the information should be used as references for any paleoimaging study. The most valuable projection of the skull is the lateral. In many cases, it will reveal characteristics that indicate the sex of the individual, such as presence or absence of a

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Figure 2.30A  An AP radiograph of the right hip of a Guanajuato mummy (MH7) with an apparent fracture (arrows) of the pelvis.

browridge and external occipital protuberance, and it will provide an overview of the dentition. To obtain a lateral projection of the skull, the interpupillary line should be perpendicular (Figure 2.32A), and midsagittal lines should be parallel to the image receptor (Figure 2.32B). Positioning can present a problem in cases where there has been intentional cranial modification. In order to more completely evaluate the dentition, right and left oblique projections of the mandible and maxilla may be necessary. However, to obtain these views, particularly on flexed remains, a great deal of manipulation of the x-ray tube and image receptor will be necessary (Figure 2.33). For the optimal images, the side of the mandible and maxilla of interest should be parallel to the image receptor. The opposite side should be rotated to eliminate superimposition. There are several methods to acquire an anterior-posterior (AP) (Figures 2.34A and 2.34B) or posterior-anterior (PA) (Figure 2.35) projection of the skull. Taking into considerations the objectives of the study, a radiologist should be consulted to determine which projection would most clearly demonstrate the structures desired. In cases of mummified remains, an AP or PA and lateral projections of the chest and abdomen should be acquired. Although dehydrated soft tissue structures are not usually visualized on conventional radiographs, when those tissues are calcified, such as lymph nodes or plaque within arteries, they are clearly seen (Figure 2.36). The lateral view will not only provide a second projection to assist in determining the spatial location of any

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Paleoimaging: Field Applications for Cultural Remains and Artifacts

Figure 2.30B  With the body rotated, the extent of the fractures (arrows) became clearly delineated.

Figure 2.31A  An AP chest radiograph taken of the Soap Lady mummy at the Mütter Museum of the College of Physicians. Because the radiograph is a two-dimensional image, it is not possible to determine the exact location of the large radiopaque object in the chest.

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Figure 2.31B  Because the mummy could not be rotated, the cassette (arrow) was angled beneath the table to obtain an oblique projection.

Figure 2.31C  The oblique radiograph of the chest conclusively demonstrated that the radiopaque object (arrow) was located outside of the mummy’s body along the posterior aspect of the back.

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Paleoimaging: Field Applications for Cultural Remains and Artifacts

B

A

Figure 2.32A  For a lateral projection of the skull, the interpupillary line (A) should be per-

pendicular to the plane of the film (B). Although there appears to be a great deal of distance between the skull and the film, with a slow speed intensifying screen, the image will be magnified without a tremendous loss of detail.

A

B

Figure 2.32B  The midsagittal line (A) should be parallel to the plane of the film (B) to minimize rotation on a lateral skull projection.

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C B

A

Figure 2.33  Since the mummified remains are immobile, positioning for an oblique mandible is complex. The center ray of the x-ray beam (A) must be directly beneath the side farthest from the film. To enhance separation of the mandibular bodies, the plane of the film (B) should be slightly angled, 15° to 20°, from a plane parallel to the sagittal plane of the skull (C).

calcifications but will also afford a prospective of the spine with less superimposition (Figure 2.37). The mummy’s joints, including shoulders, wrists and hands, hips, knees and ankles, should also be radiographed. An attempt should be made to obtain as close as possible to AP or PA projections of the joints to document degenerative changes. With the exception of remains in a flexed position and possibly hands and wrists on extended mummies, C

A

B

Figure 2.34A  For an AP projection of the skull, the line extending from the outer canthus of the eye to the external auditory meatus, known as the canthomeatal line (A) should be perpendicular to the plane of the film (B). The center ray of the x-ray beam (C) should be directed through the midpoint of the browridge, the glabella, and perpendicular to the film plane.

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Paleoimaging: Field Applications for Cultural Remains and Artifacts

Figure 2.34B  The resulting AP skull projection. It will be noted that the orbital content in this projection is obscured by the petrous ridges projected into the structure.

superimposition should not be a problem. In order to eliminate superimposition, a nonscreen film holder may be placed underneath the hands and wrists (Figures  2.38A and 2.38B). Devices to Maintain the Position of the Remains As previously stated, proper positioning is required to obtain the most information from a radiographic image. However, to acquire that image, both the remains and the image receptor must maintain the precise position during the duration of the x-ray exposure. Cardboard and other solid materials are radiopaque, impeding the passage of x-rays and causing the material to be visible on the processed radiograph. The positioning aid must be radiolucent, or “nearly invisible,” to x-rays. There are commercially available foam shapes such as wedges and blocks that are used routinely in imaging facilities (Figure 2.39), but they are expensive and bulky to transport. Generally, foam pads can be purchased in any large city or town near to where the study will be completed. Foam pads of various thicknesses can be purchased and then cut into required shapes (Figure 2.40).

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C E

B

D

A

Figure 2.35A  Positioning for a PA Caldwell projection of the skull. The canthomeatal line (A) should be perpendicular to the film plane (B). In order to achieve the correct angle, a commercially available positioning aid (C) was placed between the skull and the cassette. The center ray of the x-ray beam (D) was directed to form a 15° caudal angle to the canthomeatal line (A) and exited through the glabella (E).

Figure 2.35B  Unlike an AP or PA skull where the petrous ridges are projected within the orbits, in an AP or PA Caldwell projection the petrous ridges (A) are found near the inferior margins of the orbits.

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Paleoimaging: Field Applications for Cultural Remains and Artifacts

A

B

Figure 2.36  An AP chest radiograph of George/Fred demonstrated two radiopaque structures (A) that were suspected to be calcified hilar lymph nodes. The second object (B) appeared to be a coin within the chest.

For skeletal remains, positioning aids are also necessary. Since only minor adjustments may be required and individual bones are not very heavy, small pieces of foam padding will achieve the desired results (Figures 2.41A and 2.41B). Devices for Holding the Image Receptor The image receptor, or film–screen system, holding device requires careful consideration and creative design in order to obtain the position required. At established imaging centers, standard devices are built into the fixed system and lack the flexibility that may be required to obtain the necessary projections. Historically, radiographers conducting portable radiographic procedures in a patient’s room or trauma cases in emergency room situations may have been challenged to improvise an image receptor holding device, such as a wastebasket (Figure 2.42). In the field, the film-holding device can be constructed from materials at or near the site. Sometimes, what is required can be found in dumpsters. Cardboard and duct tape generally seemed to factor strongly in the design and configuration of many of the filmholding devices in the field. Cardboard boxes with tunnels cut through them to pass the subject through work quite as well as film holders (Figure 2.43). Since it can be easily cut to desired lengths, PVC pipe can be used as a film-holding device. Lengths of pipe can also be easily angled, allowing for various projections (Figure 2.44). When using a suspended x-ray tube support system, the subject can be placed on spacers, allowing the film to be placed underneath the subject (Figure 2.45). Creative film-holding devices require ingenuity, critical thinking, and common sense. For example, the device needs to be flexible and also sturdy enough not to collapse onto the subject under study. One can even construct a suspended sling from string, cloth, or rope

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B

A

Figure 2.37  Lateral chest radiograph confirming that the two radiopaque structures (A) were calcified hilar lymph nodes and that the coin (B) was within the chest cavity.

to hold the film above the subject (Figure 2.46). Using these varied film-holding methods, nearly every clinical position can be replicated and data regarding anatomical structures can be collected. Given the creativity required to apply conventional radiography in a field situation, several unique technical challenges may arise. The following technical challenges and their solutions are intended to stimulate the reader’s mind and broaden the scope of application of conventional radiography.

Unique Technical Challenges Field imaging by its very nature is conducted in poorly controlled conditions under unpredictable circumstances. The paleoimaging team needs to be aware of and anticipate many unique challenges in order to accomplish the objectives of a given imaging study. Efforts need to be made to be efficient and creative in an attempt to conserve resources and collect the best possible images. Experience-based challenges to field imaging research with problem resolutions are presented below.

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Figure 2.38A  An AP pelvis radiograph of George/Fred with the left hand superimposed over the ilium, sacrum and coccyx.

Multiple Images on One Film  Since x-ray film is a precious commodity in the field, as much of the film surface as possible should be utilized. An example of this situation is apparent when the objects to be imaged are smaller than the x-ray film, such as individual bones from a disarticulated skeleton. Although disarticulated skeletal components present less complex imaging challenges than experienced in the examination of mummified remains, careful planning is still necessary. In order to optimize film use, several objects of similar density can be placed on the surface of a cassette film holder, and a single exposure can be taken to produce an image of multiple components.

Figure 2.38B  A nonscreen Polaroid image of the left hand.

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Figure 2.39  A skull being stabilized with commercially available radiolucent positioning

devices.

If multiple projections of a singular skeletal component, such as a skull, or images of multiple objects that vary in density are desired on a single sheet of film, each object may be exposed individually. The procedure is achieved by dividing the film into sections, such as halves or quadrants, with the unexposed sections being partitioned by lead shielding. In order to minimize the weight of the equipment that is transported to the field site, local shielding materials, such as rocks or concrete blocks found at the study site, can be substituted for the lead shielding. After the first exposure, the exposed area is covered, and the next section of the film to be used is uncovered. The procedure is repeated until the entire

Figure 2.40  Foam purchased locally in southern Peru used to position this Chiribaya mummy.

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Paleoimaging: Field Applications for Cultural Remains and Artifacts A

C

B

Figure 2.41A  The cervical, thoracic, and lumber vertebrae were positioned for a superior-

inferior (SI) projection. Small pieces of foam (A) were employed to stabilize certain vertebra and ensure that the vertebral bodies were parallel to the film plane. Note that the number of the specimen (B) in lead numerals was placed on the cassette along with a marker (C) to indicate the right side.

surface of the film has been utilized (Figures 2.47A and 2.47B). A simple grid system using tape can be designed on the surface of the film cassette to ensure there will be little or no double exposure situations. Low-Density Objects: Too ἀ in  Taphonomic conditions, such as an acidic peat bog, will decalcify remains, rendering the skeletal system nearly radiolucent. This decalcification reduces the density and renders any residual bony structures virtually invisible to x-rays when using standard exposure settings. A pair of bog mummies, found in 1904 near the town of Weerdinge and now in the collection at the Drents Museum in Assen, the Netherlands, was the focus of a field radiographic examination (Death in a Bog 2002). The minimum factors that could be set on the 1952 vintage Picker Field Army x-ray unit used

Figure 2.41B  The resulting radiograph of the vertebrae positioned for the SI (superior-inferior)

projection.

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B A

Figure 2.42  A wastebasket (A) can serve as a satisfactorily cassette (B) support for a cross-table radiograph where the x-ray (C) is directed horizontally.

in this study were 45 kVp, 10 mA, and 1/2 s. Even at the lowest settings, the exposure was too much to demonstrate the low-density structures resulting in an image that showed no evidence of skeletal structures (Figure 2.48). There are two conventional approaches to reducing the x-ray output or the mAs. The first is to directly decrease the mAs. However, since the mA was already at the lowest setting, exposure time was the only other factor that could have been reduced. Unfortunately, because the timing device was a spring-loaded mechanism similar to a common egg timer, there was no way to reliably lower the time setting with any accuracy. A second approach to decreasing the exposure is to increase the distance. If the distance could be doubled from 40 in. (101 cm) to 80 in. (203 cm), the quantity of radiation reaching the image receptor would be quartered (see inverse square law). However, there was not sufficient tubing material to raise the x-ray source up to 80 in. (203 cm) (Figure  2.49). After noticing a black

Figure 2.43A  A cardboard box cut to form a tunnel to pass the mummy through.

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Figure 2.43B  Mummy within the cardboard tunnel and a cassette (arrow) positioned on top

of the tunnel.

aluminum material that was used for lighting, it was decided to create a filter using the aluminum. Several layers of the material were taped over the x-ray tube aperture (Figure 2.50), which effectively absorbed about 50% of the lower energy portion of the x-ray beam before it reached the mummy (Figure 2.51). This resulted in a satisfactory exposure, adding valuable data to the imaging study. Cannot Get Two Views, or When Two Views Just Are Not Enough  As previously stated, radiographs are two-dimensional images of three-dimensional objects, and at least two projections or views are necessary to provide an idea of the spatial orientation of structures within a body. However, even with a second projection at 90°, superimposition can still make it difficult to determine the relative position of objects. Photographs have always

B

A

Figure 2.44  PVC pipe was used to produce the angulated frame to support an x-ray cassette (A) held in place with duct tape. The x-ray tube (B) was resting on the table in order to achieve the necessary angulation of the x-ray beam.

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A

B

Figure 2.45  Two 1 × 3 in. (2.5 × 7.5 cm) pine boards (A) provide the space required to form a “tunnel” beneath the mummified remains to accommodate the cassette (B).

had a similar problem in separating objects from the background, middle ground, or foreground. In 1843, Sir David Brewster invented the lenticular or refracting stereoscope, which was adapted into the hand stereoscope used in photography (Eisenberg 1992c). Since over 50 years had elapsed before Roentgen’s announcement of his discovery, it wasn’t long before the popular illusionary photographic method would be applied to x-ray imaging. In March

Figure 2.46  A tape sling used to support the Polaroid cassette above the chest of a mummy in Guanajuato, Mexico.

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Paleoimaging: Field Applications for Cultural Remains and Artifacts

Figure 2.47A  Rocks utilized to permit multiple exposures on a single cassette.

1896, Elihu Thomson suggested using the stereoscopy in radiology (Eisenberg 1992d), and it was quickly adapted for complex anatomical regions such as the skull, chest, and pelvic areas (Files 1962a). Prior to the advent of other modalities, particularly computed tomography, stereoradiography was routinely taught to student radiographers. As with many radiographic procedures, there are several approaches to obtaining stereoradiographs. The first, and most common, requires a linear shift of the x-ray source at a ratio of 1:10 (Files 1962b; Cahoon 1965a). If the SID is 40 in. (101 cm), then the total tube shift should be a total of 4 in. (10 cm), 2 in. (5 cm) in either direction from center. For optimal results, the direction of shift was specified to be at right angles to the predominating lines of the part being radiographed. The “predominating lines” in the thorax are the

Figure 2.47B  A radiograph of two cervical vertebrae where rocks were used to permit three positions on a single film.

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Figure 2.48  The overpenetrated and overexposed initial Polaroid image of the left arm of the Weerdinge mummy.

Figure 2.49  The set-up for the Weerdinge mummy study. The x-ray tube was at the maximum distance from the mummified remains.

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Figure 2.50  Several layers of the black aluminum (arrows) were taped over the window of the

x-ray tube.

Figure 2.51  The resulting radiograph after the beam had been filtered. The radius and ulna were clearly visible.

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B

A

Figure 2.52  A Stanford x-ray stereoscope. One of the pair of images was placed on each view box (A) and aligned while looking through the viewer (B).

ribs, so the direction of the shift should be longitudinally, along the vertebral column. For stereo images of the long bones, the shift would be transversely across the bones. Since the skull is a complex structure with bony components along several planes, it is the exception, and the shift may be in either direction depending on which structures are to be visualized (Cahoon 1965b). Stereoradiography was routinely employed in chest radiography prior to the advent of computed tomography. This was a common procedure, particularly during the period when tuberculosis was epidemic in the United States. Stereo viewing devices were constructed specifically for viewing the image that provided a “suggestion” of depth of field (Figure 2.52). There are two important considerations in acquiring satisfactory stereo projections. The first requirement is that the object under examination must not be moved between exposures. To achieve this goal, the object must be elevated to create a space to accommodate the film. If there is an x-ray table available, the tray under the table would provide more satisfactory results. However, if the x-ray table approach is selected, there is an additional consideration. In medical imaging, the tray under the table is employed when body parts are thicker than about 4 in. (10 cm). Since higher kV is required to penetrate the thicker body parts, more scatter radiation will be produced. In order to minimize the scatter reaching the film, a device termed a grid is built into the top of the tray mechanism. The grid is composed of parallel lead strips. In some x-ray tables, the grids will move back and forth in a transverse direction or reciprocate during the exposure. More commonly called

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C

A B

Figure 2.53A  George/Fred was placed on the x-ray table transversely. The long axis of the table is in the direction of the yardstick. The center ray of the x-ray beam would be directed to the center of the chest (A). For the first exposure, the center ray was shifted 2 in. (5 cm) to the right (B). A total 4 in. (10 cm) shift to the left (C) was the center for the second exposure.

A

B

Figure 2.53B  The resulting CR image of the first exposure processed on a Konica medical CR system. Note the relative position of the calcified hilar lymph nodes (A) and the radiopaque artifact (B).

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Figure 2.53C  Because the radiopaque object is more distant from the liver, there is a greater shift of the object on the second image. Since the relative position of the calcified nodes are closer to the spine, the shift in position is not as great.

a Bucky, after one of the individuals who developed the device, the motion of the device eliminates any shadow of the lead strips from appearing on the image and is more efficient at capturing the scatter radiation. In other tables, the grid is fixed in position above the tray, and close inspection of the resulting image will reveal the linear shadows of the lead strips. In either case, the central ray of the x-ray beam must be centered on the midlongitudinal axis of the x-ray table. Moving the central ray transversely across the table will result in a portion of the beam being absorbed by the grid; this is termed grid cut-off. Therefore, the second requirement, if the tray under the table is going to be employed, is that the shift must be along the center line of the table. The transverse x-ray tube shift technique was employed to get a perspective of the calcified hilar lymph nodes on a mummy known as George/Fred. In order to employ the transverse shift, the mummy had to be placed transversely across the x-ray table. In that position, his chest was over the center of the table and the Bucky tray beneath it (Figures 2.53A, 2.53B, and 2.53C). The second approach to stereoradiography is based on angular rather than a linear shift. Either the body or object can be rotated between 6° and 8° (Carlton and Adler 1992) or the

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Figure 2.54  The cobra coffin from the Rosicrucian Museum in San Jose, California.

x-ray source can be angled a total of 5°. The latter method was employed on a small Egyptian cobra coffin at the Rosicrucian Museum in San Jose, California (Mummy Menagerie 2003). The imaging challenge was to identify the contents of the small wooden coffin that had the approximate dimensions of 4 × 4 × 7 in. (10 × 10 × 18 cm). The coffin also had a snakelike carving mounted on its lid (Figure 2.54). The museum curator wanted to know what was in the coffin but did not want to risk opening the fragile artifact. A Polaroid image quickly demonstrated the skeletonized remains of at least one but possibly two snakes. Because the remains were on the bottom of the box, a lateral projection would only show superimposed skeletal elements. Since the remains were fragile, the box couldn’t be tilted for an oblique projection. Although an oblique view could have been obtained by keeping the coffin flat and angling the film and x-ray source, the edges of the box were so close that they would end up superimposed over the skeletal remains. A stereoradiograph could provide the information necessary. The coffin was built up on foam with a space to place the film behind it. On the first exposure, the x-ray tube was directed horizontally with the center of the x-ray beam directed to the center of the small box. The film was changed and the second exposure was taken with the x-ray tube angled 5°, but the central ray was still directed through the center of the coffin (Figure 2.55). When viewed stereoscopically, two snake skulls were noted, demonstrating the value of this stereoradiographic technique (Figure 2.56). Positioning Challenge: Going for the Long Shot  In field imaging, it is often the case that the “subject” cannot be moved. In addition, the x-ray tube and/or image receptor may not be able to be placed in an optimal position to collect the desired data. In these cases… go long! The approach is straightforward and follows the aforementioned direct square law: as the SID increases, the mAs, particularly the exposure time, must be increased. In order to determine the proper exposure values when using a “long shot,” an acceptable

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Figure 2.55  The setup for one of the two stereoradiographs of the cobra coffin.

exposure for a shorter distance can be inserted into the inverse-square formula (mAsnew = mAsold[Distanceold/Distancenew]2). While working in Lima, Peru, on the collection of mummy bundles from the site known as Purachuco, a lateral projection of the skull of a mummy was required (House of Bundles 2002). The mummy was in a supine position on an examination table. The head was turned to the right, but due to the fragile state of the remains, the mummy couldn’t be rotated. The only location to place the x-ray tube that matched the angle of the head was on the edge of a loft above the mummy (Figures 2.57A and 2.57B). Acceptable images of other areas of the body were obtained using 10 mAs at 48 in. or 4 ft (122 cm). The new SID was

Figure 2.56  Stereoradiographs of the cobra coffin.

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A

B

Figure 2.57A  The relative position of the x-ray tube (A) and the mummy (B) looking up at the

loft.

approximately 16 ft (488 cm). The following calculation was employed: (new distance/old distance)2; (16/4)2 (10 mAs) = (4)2 (10 mAs) = 16 (10 mAs) = 160 mAs. It is important to recall that the longer the exposure time, or when using multiple short exposures, the greater is the risk of overheating the x-ray tube. Cooling-off periods between multiple exposures must be employed and, when indicated, external cooling of the tube may be required. Therefore, four exposures, each at 40 mAs, were taken with a 30 s pause between exposures. The result was a usable lateral skull x-ray completing the data set for that mummy (Figure 2.58). Will Not Fit on the Film: Too Big  The largest-size medical x-ray cassette is 14 × 36 in. (35.6 × 91 cm), which could accommodate the entire spine on a single image for scoliosis studies. It would seem logical to take two separate standard 14 × 17 in. (35.6 × 43.2 cm) cassettes and then, once processed, simply put the images together. Unfortunately, it’s not that simple. Why? The answer has to do with a basic property of the x-ray beam: it diverges from the source. The only portion of the x-ray beam that is vertical is at the center of the cone of divergence. If two views were taken, let’s say of an entire leg, on the smaller cassettes the first would be centered over midfemur and second, over midtibia and fibula. The knees on the two processed images wouldn’t match up. Many instances arise in field research situations when the object is larger than the largest image receptor available. To avoid the issue of beam divergence and to acquire a single image of a large object can be problematic. This problem can be resolved by using multiple, slightly overlapped sheets of film to form a single, large image receptor. In addition, it should be noted that the SID must be sufficient to cover the entire film surface.

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A

B

Figure 2.57B  The relative position of the x-ray tube (A) and the mummy (B) looking down

from the loft.

Finally, using the direct square law, an exposure time can be calculated. If the desired results require a nonscreened image, along with the increased SID, additional increases in the exposure time will be necessary. Imaging the object in this manner, once processed, the individual images can be “stitched together” with commercially available photography processing programs such as Photoshop®, creating a seamless, single, complete image of the oversized object. Polaroid film worked well for this application. Since the Polaroid film was already in a light-tight flexible envelope, the film packets were easily fixed in place to a surface with masking tape in order to create a “single” large image receptor. An example demonstrating the use of multiple Polaroid film envelopes to produce a single image of a baboon mummy will be presented in Chapter 9. The procedure can be done with a number of cassettes; however, with multiple overlapping cassettes the metal edge of each cassette would be superimposed on the adjacent film, creating an artifact on the developed image. If instant film, such as Polaroid, is not available and if cassettes are to be used as the image receptors, the subject must be supported by a sheet of Plexiglas or some other radiolucent material. The support would permit cassettes to be put into place or removed, one after the other, from under the Plexiglas. In this way, the imaging can be conducted without moving the subject. A lateral radiograph of the Soap Lady mummy at the College of Physicians Mütter Museum in Philadelphia, Pennsylvania, will provide an example of “merging” multiple images. As part of a proposed new display, a complete AP and lateral radiograph of the entire mummy was needed. To acquire the lateral projection, a 14 × 36 in. (35.6 × 91 cm) was selected and a track was constructed (Figure  2.59) to support the cassette over the entire length of the mummy. In order to

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Figure 2.58  The nearly lateral radiograph of the mummy’s skull. Although the humerus (arrow) partially obscured the maxilla and mandible, it was possible to determine that the mummy was edentulous.

Figure 2.59  A lateral projection cassette support system was constructed with a 32 × 12 × 3/4 in. (81.2 × 30.5 × 1.9 cm) plywood base (A). A 36 in. (91.4 cm) long, 7/8 × 1/2 in. (2.2 × 1.29 cm) aluminum track (B) that held the cassette was mounted on a 28 in. (71 cm) long, 1½ × 1½ in. (3.8 × 3.8 cm) pine board (C). Once the support system was in place, counterweights, such as sand bags, were placed on the plywood to stabilize it.

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Figure 2.60  Without moving the x-ray tube, multiple lateral images of the Soap Lady were

taken, processed, scanned with a flatbed scanner with transparency adapter, and assembled to produce a single lateral image.

cover the entire mummy, the x-ray tube was placed at a 140 in. (356 cm) SID. A total of four exposures were taken, digitized on a flatbed scanner with a transparence adapter and “assembled” to create a single image (Figure 2.60). A nonscreen approach is by far the easiest and provides the greatest flexibility. A film support can be constructed using a sheet of Foamcore cut to the desired size. In the darkroom, conventional radiographic film is placed onto the support and held in place using thumbtacks. There should be at least 1/2 in. (1.25 cm) of overlap as each additional sheet of film is fixed to the surface of the support. Once the films are all in place, six layers of black gardening plastic or a single layer of black pool liner are used to make the “film holder” light tight. Duct tape should be used to secure the covering material. Using this nonscreened method, an image receptor of virtually any size can be constructed. We used this nonscreened Foamcore film holder approach on an articulated 84 in. (213 cm) skeleton also at the Mütter Museum in Philadelphia. The individual, who suffered from gigantism during life, was mounted in a cabinet with two other mounted skeletons. The giant’s skeleton could not be removed from the case for a radiographic study. There was insufficient space to get the required distance to cover a film holder over 90 in. (229 cm) tall (Figure 2.61). Therefore, two Foamcore support film holders were constructed. As previously described, the images were scanned in and “stitched” together (Figure 2.62). Among the imaging findings was a lack of organized trabecular pattern within the proximal femurs, suggesting the bones had not been subjected to weight-bearing stresses for several months prior to the individual’s death. Several factors should be taken into consideration before this procedure is undertaken. Since long distances are required between the image receptor and x-ray source, long exposure times will be needed. In addition, if film will be exposed directly without the amplifying effect of intensifying screens, the exposure times could require a total of minutes. Therefore, if many specimens are going to be imaged using this method, the high heat loading of the x-ray tube will reduce the tube “life.” Cannot Come out of the Cave: Redefining Portable  Whenever possible, radiography should be conducted in situ or as close to the recovery site as possible. This approach preserves the context and allows assessment of the mummified remains or artifacts to be made prior to moving or transport. Many field situations arise in which the subject cannot be moved due to its fragility or because of local cultural customs. In these situations, the term portable takes on greater meaning. In one example, we were to radiograph and conduct endoscopy on the mummified ancestral remains of the Ibaloi people that had been placed in caves deep in the Kabayan Jungle on the island of Luzon in the Philippines (Cave Mummies of the Philippines 2002). Local customs would only permit the remains to be moved around within a cave, and they could not be removed from the caves for study. The

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C

B

A

Figure 2.61  The setup employed to radiograph the Mütter Giant. The x-ray tube (A) was positioned to take an AP projection of the lower portion of the legs. The nonscreen black plastic film holder (B) was resting against the sheet of Foamcore (C).

challenge was to establish an imaging facility at the mouth of these remote caves. A gasoline generator was required to provide power for the radiographic and endoscopic instruments. The generator was strapped to a long pole and carried to the caves by two members of the Philippine Army who also served as a security team. The x-ray unit was a compact 1952 vintage U.S. Army field unit stripped down to its bare necessities and the image receptor was 8 × 10 in. (20.3 × 25.4 cm) Polaroid® Type 803 film. The “higher-speed” or “faster” Polaroid film was selected in order to reduce the exposure time by a factor of eight. The x-ray tube and image receptor support devices were fashioned with whatever was available in or around the cave. The tube was often balanced on rocks in the cave, with the film being supported by an ancient coffin or small stones (Figure 2.63). The images provided information related to the age at the time of death and remnants of soft tissue (Figure 2.64), substantiating the villager’s claims of embalming procedures. The quality of the radiographs demonstrated that imaging studies can be conducted in extreme settings. Cannot Get the Cassette under/behind Subject  Superimposition has been mentioned several times as a disadvantage of conventional radiography. The problem is compounded by mummified remains, whether they are in a flexed or extended position, due to the

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Figure 2.62  The assembled AP and lateral radiographs of the Mütter Giant. (Images courtesy of Andrew Nelson, PhD.)

immobile position of their extremities. Not only might an arm or a hand obscure a clear view of, for example the spine, but it may also make it difficult to make an assessment of the extremity itself. Since there may not be enough space for a cassette with intensifying screens to fit between the anatomical parts of interest, a flexible nonscreen film holder might provide a solution. An example of this flexible nonscreened film holder approach was demonstrated in the study of a sideshow mummy. Sideshow mummies were uniquely American phenomena. Unclaimed bodies, embalmed with either arsenic or formalin, were procured by entrepreneurs and incorporated into the traveling entertainment circuits that were popular in the late 19th and early 20th centuries. In order to attract paying costumers, sideshow promoters would create an incredible story surrounding the individual’s life and subsequent demise and our example, Hazel Farris, was no exception (An Unwanted Mummy 2001). Her legend stated that she was the wife of a man in Louisville, Kentucky. They both had a history of drinking and domestic disputes. One night, Hazel told her husband that she wanted to buy a hat, he said no, and so she shot him dead. Three sheriff’s deputies came to investigate, and she shot and killed all of them. The sheriff came in and entered into a scuffle with Hazel during which her ring finger was shot off. Hazel then bested the sheriff

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Figure 2.63  The setup employed to radiograph the Ibaloi mummy within the cave.

and shot him dead as well. Hazel fled back to her home in Bessemer, Alabama, where she became a “lady of the night.” Hazel confessed her crime to a lover, who decided to turn her in for a $500 reward that was placed on Hazel. Hazel didn’t want to go to jail, so she committed suicide by drinking arsenic in whiskey. Or so the story goes. The missing ring finger became important to the study to determine whether it was a pre- or perimortem event. Unfortunately, the hand was crossed over the body and, even with angled projections, an unobstructed view, free of superimposition, wasn’t possible (Figure 2.65A). However, there was sufficient space to slide a Polaroid film packet between the hand and the lower abdomen (Figure  2.65B). The result was an image of her hand free of superimposition and the finger in question appeared to have been amputated well before the time suggested by the story that brought people into the tent to view her remains (Figure 2.65C). In another field imaging case, there was inadequate space beneath or on the side of the mummy to accommodate a cassette. The mummy, known as Princess Anna, was at rest in Kastle, Germany (Princess Baby 2002). The legend states that Anna was the daughter of King Ludwig IV and died while in the Kastle region. The distraught king ordered that she be preserved for eternity. Friars mummified Anna, and she is currently interred in a wooden case at the church in Kastle. Due to her fragile state, the remains couldn’t be lifted high enough to permit the rigid cassette to be placed underneath the body. In addition, her left shoulder was so close to the side of the case that it precluded the use of a

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Figure 2.64  The excellent state of preservation is demonstrated by the presence of tracheal rings (arrows) seen on this lateral chest radiograph of an Ibaloi mummy.

Figure 2.65A  The Polaroid image of Hazel Farris’ hand superimposed over her abdomen, making it impossible to assess the condition of her fourth finger (arrow).

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Figure 2.65B  The Polaroid film packet (arrow) placed between the right hand and the

abdomen.

cassette for lateral projection. The nonscreen approach provided a solution for both problems. The flexible nature of the Polaroid film package allowed it to be smoothly positioned behind the mummy with minimal manipulation (Figure 2.66). The packet had sufficient stiffness to be slid between the shoulder and side of the case without curling onto the body (Figure 2.67). Summary of Unique Technical Challenges With the preceding presentation of the various technical challenges associated with field radiographic research, the authors hope that the reader will be better prepared to plan and execute conventional radiography in alternate settings. Although the list of challenges presented here may not be complete, it represents many of the major considerations and stresses that the preparation is a critical and integral part of field radiography.

Figure 2.65C  The nonscreen Polaroid image of the right hand, clearly demonstrating the remaining portion of the fourth proximal phalange (arrow).

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Figure 2.66  The AP of Princess Anna’s pelvis, showing Harris’ lines (arrows) on the iliac

crest.

Technical Advantages and Disadvantages of Conventional Radiography Technical Advantages The advantages of conventional radiography for field applications are numerous. Conven­ tional radiography provides the ability to “see” within objects such as mummy bundles, coffins, and wrapped artifacts. In addition, radiographs allow for the assessment of structures within structures. For example, not only can the radiograph provide an image of skeletal structures within a wrapped bundle, but it may also reveal a tumor within the bones. Radiography can be portable, making it possible to image skeletal and mummified remains and artifacts at or close to the recovery site. It is the optimal modality for initial

Figure 2.67  Lateral image of the mandible clearly visualizing unerupted teeth (arrows).

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examination in that it may minimize damage to potentially fragile remains with least disruption of taphonomy. The initial radiographs can be used to determine the necessity and objectives of advanced imaging procedures and may help direct conservation efforts. The radiographic unit is usually durable and reliable as long as it is packed well for travel and not used beyond its capabilities. Photographic paper using a Polaroid screened or nonscreened cassette provides maximum flexibility in getting the desired images with minimal waste and without the need for developing chemistry. Technical Disadvantages The major disadvantages of conventional radiography include the need for electric power, the superimposition of shadows, and the transportation of radiographic film. Without digital manipulation, conventional radiography produces a single image at a particular exposure setting. The “shades of gray” on the processed radiograph can’t be altered as compared to computerized radiographic modalities, in which density and contrast can be manipulated without having to repeat an exposure. Also, magnification and distortion of objects on the developed film preclude direct measurements off the images. Another major disadvantage of conventional radiography is the misuse of the technology by noncertified radiographers. In the United States, individuals must complete a minimum 24-month program to be eligible for a national certification examination. Even the entry-level radiographer would probably not have sufficient experience to formulate a plan for the establishment of a field radiographic facility. Their education is primarily based on producing acceptable radiographs of living patients with hydrated tissues. However, their knowledge base is sufficient to make adjustments in technical factors such as kVp and mAs. In addition, their ability to position patients can easily translate into manipulating mummified and skeletal remains to achieve the required projections. Individuals unfamiliar with the application of basic imaging principles, particularly for conventional radiography, will be less successful in producing diagnostic images of mummified and skeletal remains. Tremendous amounts of information will be missed or rendered useless because the images are either under- or overexposed. Even with correct exposure variables, there will be a loss of time and film, decreasing the efficiency of the imaging project. Probably of greater significance, improper application of conventional radiography by untrained individuals can result in catastrophic failure of the x-ray tube due to overheating. A damaged x-ray tube can also leak cooling oil onto specimens, causing irreparable damage. If the x-ray tube fails, particularly in a remote location, the radiographic phase of the study is over.

Complementary Data Acquisition Although the conventional radiograph provides critical information regarding contents of wrapped remains, the images are “shadows” with few descriptive characteristics. In the absence of advanced imaging, the complementary nature of endoscopic imaging cannot be understated. The endoscope, provided there is an entry route, can provide additional characteristics such as color, shape, and imaging of low-density objects or anatomical features. We have found that the field application of both modalities increases the obtainable data, adding to the interpretability of those data. The complementary nature of paleoimaging modalities will be demonstrated through the various case studies presented in this text.

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The information from conventional radiography will certainly contribute to the decisions regarding safe transportation of the remains or artifacts to a facility for advanced imaging methods. The conventional radiograph often provides information about the integrity of the remains and whether or not there are focused points of interest indicating the need for further imaging analysis.

Anthropological Applications: Laboratory and Field Objectives for Conventional Radiography The application of conventional radiography to anthropological research and data collection should be objective driven. That is, the formulation of a field imaging program should be designed to answer specific anthropological and archaeological questions. Often, radiography is conducted using a narrow scope of objectives, thereby limiting the data collected. It has been demonstrated that conventional radiography can make a wide variety of information available to researchers without having to disrupt the remains or artifacts. The following objectives are considered minimal and have proved to be obtainable through the application of conventional radiography. The objectives are divided into two broad categories: fundamental and refinement objectives. Fundamental objectives are those objectives that should be achievable in most cases. Refinement objectives are those objectives that have the potential to refine the data collection and add to the information derived. The refinement objectives may not be achieved but should be considered in every case. Fundamental Objectives Assess Condition of the Remains or Artifact Initially, conventional radiographs can help researchers determine the fragility and integrity of the remains or artifacts under investigation. The initial radiographs may help determine if a mummy or artifact is safe to move. The radiographic information collected to address this initial objective is best carried out at the exact location of the study subjects. The location may be a tomb, a cave, a remote research facility, or a museum. In each case, a radiographic examination reveals information that can be used to direct further study activities. These activities include those that can be conducted on-site and suggest studies using advanced imaging. The radiographs may also indicate the direction for possible conservation measures. One example is that of an on-site field examination of the mummies of Urbania, Italy, at the Church of the Brotherhood of the Good Death (Mama Mia Mummies 2003). These accidental mummies are on display behind the main portion of the church. The mummies were displayed in an upright position and were held in place by fragile wires. The initial conventional radiographs, conducted with the mummies in place, demonstrated that the remains were too fragile to be moved and severely limited future imaging research (Figure 2.68). Age at the Time of Death The next fundamental objective is to aid in the determination of the age at the time of death. The age at time of death can be determined by radiographically documenting the eruption pattern of the teeth, overall dental condition, overall bone and epiphyseal development, fusing patterns of skull bones, and degenerative changes. For individuals under

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Figure 2.68  The AP radiograph of the chest of a mummy (U18) from Urbania, Italy, showing the remains were held in place by wire. Since a number of the skeletal components appeared to be disarticulated, it was determined that the remains could not be moved.

approximately 25 years of age, the age assessment should be made using dental eruption patterns and an evaluation of as many epiphyses as can be visualized. Each of these data can then be compared to standardized anthropologic aging charts to assess age at the time of death. For individuals over the age of 25, data such as degenerative changes and dental wear need to be considered along with cultural characteristics such as the physical environment, diet, and work patterns of the culture being studied. The trabecular patterns within certain structures of long bones, such as the femoral neck and calcaneous, can also provide an estimation of age and can only be visualized radiographically. An example of determining age at the time of death can be found in the case of Princess Anna (previously described). In this case, the recorded age at the time of death of the young princess was three years. The lateral projection of the mandible demonstrated a tooth eruption pattern that suggested her age at the time of her death was more likely around 18 months. Additional radiographs of her wrists supported the earlier age at the time of death. In this case the historical record was corrected using the radiographic data. In population studies, determining the average age at the time of death can have greater meaning when the study size is large enough to conduct statistical analyses. Determination of Sex in Absence of Direct Observation Another fundamental objective is to determine the sex of the mummified individual. Conventional radiography can be very useful if the mummified remains are wrapped or

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Figure 2.69  An AP pelvis of a Chachapoya mummy demonstrating a subpubic angle, indicat-

ing a male.

within an enclosure. Key radiographs include an AP or PA and lateral projections of the pelvis and a lateral view of the skull. Although magnification on the radiographic image precludes direct linear measurements, the calculation of angles is unaffected. However, rotation of the body part would increase distortion and complicate the calculation. An AP or PA of the pelvis would reveal the subpubic angle. An angle of less than 90° suggests a male (Figure  2.69), and greater than 90° suggests a female (Figure  2.70). On a lateral projection of the pelvis, the greater sciatic notch is a fairly good indicator of the sex of the individual (Walker 2005) (Figures 2.71 and 2.72). The presence or absence of a browridge on a lateral view of the skull can also be used to indicate the sex of an individual. The presence of the browridge suggests a male (Figure 2.73), whereas the absence of the structure suggests a female (Figure 2.74). Additionally, the prominence of the occipital protuberance can help with sex determination (Figures 2.75 and 2.76).

Figure 2.70  The greater subpubic angle seen in the pelvic radiograph of this Chachapoya mummy, indicating a female individual.

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Figure 2.71  The narrow angle of the greater sciatic notch (arrow) demonstrated on the lateral projection of the pelvis of this Chachapoya mummy suggested a male.

Radiographic assessment of the long bones in terms of their robustness or gracile appearance can add data for interpretation related to this objective. In some cases where the differentiation is not obvious, artifacts associated with the remains and demonstrated on the radiographs may suggest the sex of the individual. For example, in the Chachapoya culture of north-central Peru, a pincer, used for pulling out whiskers, is frequently included within the mummy bundle of a male (Figure  2.77) and tupu and/or spindle-whorls are found in female bundles (Figure 2.78). Dentition The conventional radiograph can provide information regarding the dental status of mummified and skeletal remains. Features such as dental wear, caries, attrition, exposed roots, abscesses, bony lesions, and an assessment of peri- versus premortem tooth loss can all be demonstrated radiographically. It is important to note that due to the superimposition of shadows, specific projections are necessary to acquire images for dental assessment. Oblique views of each side of the maxilla and mandible are required to provide an unobstructed visualization of the canines, premolars, and molars (Figure 2.79). A PA projection with the incisors parallel to the image receptor plane will provide a clear view of the incisors (Figure 2.80).

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Figure 2.72  The wide angle of the greater sciatic notch (arrow) suggested a female Chachapoya

mummy.

Refinement Objectives Detection of Pathologies (Paleopathology) The human body, its organs and tissues, constantly interact with its external and internal environments throughout the individual’s life span. Many disease processes impacting the internal environment of the organism leave revealing signs in the afflicted organ or tissue. If the individual survives the acute phase and the disease persists, those signs, which are evidence of the disease, can eventually impact the bony structures, leaving a permanent record that can survive for millennia. Unfortunately, soft tissues begin to decompose rapidly after death, and some of the signs of disease can be lost to this process. In contrast, the skeletal system will endure where organs may not and provide evidence of disease or injury, which can be detected radiographically. Some examples of disease patterns that can be seen on conventional radiographs include the following: calcified lesions in the pulmonary tissue, traumatic injury to bony structures, an assessment of fractures as to their pre- or perimortem status, shifted mediastinal structures, renal and bladder stones, lesions within bones (Pott’s disease), gross morphologic variations in organs or bony structures, the impact of lesions on bony structures (sella turcica—pituitary lesions), and pelvic configuration as related to peripartum status. Morphological anomalies such as scoliotic

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Figure 2.73  The prominent browridge seen on the lateral skull radiograph suggested a male Chachapoya mummy.

Figure 2.74  The lack of a distinctive browridge suggested this individual was a female.

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Figure 2.75  A lateral Polaroid skull of a Guanajuato mummy (MH2) demonstrating the characteristic occipital protuberance (arrow) seen in males.

Figure 2.76  A composite lateral Polaroid skull and cervical spine of Marie O’Day without an

observable occipital protuberance. The radiopaque object within the mouth (arrow) is a vulcanite denture.

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Figure 2.77  The lateral skull radiographs of two Chachapoya mummies showing the pincers (arrows) included in the wrapping, suggesting a male.

conditions can also be detected via radiography. Biomechanical stress is well recorded in the bony structures, particularly at the location of articulations. Arthritic changes and changes in bony structures as the result of repetitive activity can be demonstrated by conventional radiography. Numerous paleopathological changes can be documented radiographically: a healed fracture of a humerus on a mummified Chinese immigrant (Figure  2.81) (Gallegos et al. 2002); a depressed skull fracture in the occipital bone, without healing, in an Egyptian mummy known as the Cook of Ra (Figure 2.82); what appears to be a compression fracture of a thoracic vertebrae in the lateral chest radiograph of this Chachapoya mummy (Figure 2.83) (Bravo et al. 2001); two radiographic examples of bladder stones (Figures 2.84A and 2.84B) (Bravo et al. 2003); avascular necrosis of the hip (Figure 2.85); and calcifications of arteries within the pelvis (Figure 2.86). It is important to note that although a disease, particularly

Figure 2.78  A pair of tupus seen in the AP and lateral radiographs of this Chachapoya mummy, indicating the individual was a female.

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Figure 2.79  An oblique projection of the left mandible of a Guanajuato mummy, MM10.

one within the remaining soft tissues, may be detected by radiograph, the specific disease can only be determined by a paleopathologist. Target Identification for Biopsy and Retrieval In many cases, radiography reveals an area of interest that warrants closer study. Typically, this is a particular pathological anomaly or an artifact either within the mummy or among the mummy wrappings. If it is within the research protocols and the target is to be biopsied or removed, conventional radiography can be employed to pinpoint the spatial relationship

Figure 2.80  A PA projection on a Guanajuato mummy, MH2.

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Figure 2.81  A chest radiograph of a Chinese mummy recovered from northern Nevada. Note the old fracture of the humerus (arrow).

of that target. Clearly, the imaging modality of choice for this task is computed tomography, CT. However, in the field conventional radiography can be successfully employed to pinpoint lesions and artifacts. The object may be located by using two long needles, such as spinal needles, inserted at right angles into the approximate target location. Taking into account inherent characteristics such as magnification and distortion, the depth and direction of needle insertion are determined from the original radiographs. Radiographs taken at right angles to the needles while in place will provide an assessment of the target’s spatial relationship relative to the needles. The target, once located, can then be biopsied or extracted under endoscopic guidance.

Figure 2.82  A lateral skull of a mummy known as the Cook of Ra that was radiographed at Yale University’s Peabody Museum. Note the fracture (arrow) of the occipital bone.

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Figure 2.83  A compression fracture of a thoracic vertebrae (arrow) demonstrated on the lateral chest radiograph of a Chachapoya mummy.

Two examples using conventional radiography with needle localization are provided. In the first case, a radiopaque mass, thought to be a kidney stone, was demonstrated on the abdominal radiograph of a mummy located in a crypt under a church in Popoli, Italy (Tales of an Italian Crypt 2001). In order to remove the mass endoscopically,

Figure 2.84A  An AP pelvis image of a mummy (U6) from Urbania, Italy, with an apparent extremely large bladder stone.

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Figure 2.84B  A small bladder stone noted within the pelvis of another mummy (U18) from Urbania, Italy.

spinal needles were inserted at right angles in the suspected region to serve as a guide (Figure 2.87A). Periodically, while the endoscope was advanced, radiographs were taken to document the precise location of the device until the mass was removed (Figure 2.87B). Subsequent analysis of the mass verified it was a kidney stone (Fornaciari et al. 2002). This field application for spatial location reduces the need to move the study subject to an imaging facility, thereby reducing the risk any dislocation of the target within the internal context.

Figure 2.85  Another mummy (U5) from Urbania, Italy, with an apparent congenital dislocation of the right hip. The poor condition of the mummy was readily identified by the loose ribs in the pelvis.

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Figure 2.86  Bilateral calcified arteries (arrows) were noted within the pelvis of a mummy from Urbania, Italy.

The second case involved a sideshow mummy known as Hazel Farris. Polaroid radiographs demonstrated a radiopaque mass in the chest (Figure 2.88A). A CT examination confirmed the presence of the mass but clearly indicated that it was located within the major vessels of the heart (Figure 2.88B). Because the “owner” of the mummy had scheduled the mummy to be cremated following the examination, an autopsy was permitted. At autopsy, the heart and lungs were removed. In an attempt to correlate the location of the mass seen on the conventional radiography and the CT image, pins were placed at right angles to each other and the specimen was radiographed (Figure 2.88C) (Cartmell et al. 2002). The resulting image confirmed the location of the mass previously noted and after removal it was determined to be a hardened blood clot. Similar radiopaque masses had been noted within the vessels associated with the heart of other sideshow mummies that had been embalmed with arsenic. It was concluded that the dense clots were associated with the embalming procedure. In a recent study (Beckett et al. 2008), we evaluated another possible field technique for specific target needle biopsy using standard radiography, endoscopic guidance, and tissue target triangulation using a radiopaque “locator grid” technique.

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Figure 2.87A  A Polaroid radiograph of the left medabdominal region of the mummy from Popoli, Italy, with the two spinal needles (arrows) placed at right angles in order to locate the kidney stone.

Context in bioanthropology refers to the place where mummified remains are found as well as the surrounding environment, associated grave goods, and the relationships among these many variables. Typically, context refers to the external environment and the relationship of the mummified remains to those surroundings. Internal context refers to

Figure 2.87B  The renal stone after it was extracted from the mummy.

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Figure 2.88A  A Polaroid AP radiograph of the chest of Hazel Farris, demonstrating a radiopaque mass (arrow) located to the left of the midline.

those anatomical structures or artifacts within the mummy itself. Contextual information is critical when attempting to interpret anthropological, archaeological, and paleopathological data (Buikstra and Beck 2006). The more information and data recorded in situ, the better able those data may inform researchers about the person and how his or her biology interacted with the environment. If the internal context is disturbed, relationships between morphological features may be disrupted, which in turn may lead to misinterpretations regarding the mummified remains. In an attempt to preserve both the external

Figure 2.88B  An axial CT image demonstrating the radiopaque mass (arrow) in the heart.

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Figure 2.88C  A radiograph of the heart and lungs after they were removed from the body. Pins were place vertically and horizontally (arrows) in order to localize the radiopaque mass.

and internal context associated with mummified remains, scientific study, including tissue biopsy, should be conducted in situ. The goal of this study was to explore a possible field technique for needle biopsy in an attempt to preserve context. The study was conducted under endoscopic guidance to ensure tissue target location and penetration of the biopsy needle. The subject of this study was a late 19th to early 20th century mummified male. The subject was a sideshow mummy known as George/Fred, curated by Ripley’s Believe it or Not, which was subsequently donated to the Bioanthropology Research Institute for research and educational purposes (Figure 2.89). The mummy is that of a male whose external and internal preservation are very good, making the subject an excellent choice for organ tissue biopsy. The state of preservation of the subject’s internal organs was excellent, with cardiac, pulmonary, and hepatic organs intact. For this study, the liver was targeted for biopsy as its radiographic density indicated that the hepatic tissue was easily recognizable and accessible for biopsy.

Figure 2.89  A photograph of the mummy George/Fred.

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Figure 2.90  Locator grids positioned on George/Fred.

In field settings, using CT instrumentation to allow for guided biopsy is not practical due to size and availability. Using conventional radiography, AP and lateral radiographs were taken of the area of interest to estimate the organ target location, in this case, the liver. Two “locator grids” were constructed using standard garden fencing with 0.5 × 0.5 in. (1.25 × 1.25 cm) “windows,” which were attached to frames large enough to hold a standard 14 × 17 in. (35.5 × 43 cm) x-ray cassette. The two locator grids were constructed to produce a right angle to one another directly over and next to the subject, ensuring that the image produced would encompass the target organ region as determined by the initial set of x-rays (Figure 2.90). The grid was constructed so that the horizontal level could be adjusted. A small metallic marker was placed on each grid at the approximate location of the target organ and in the same axial plane. X-ray cassettes were placed for the AP and lateral views in a manner such that the grid and metallic markers would appear on the developed films. Using the locator grid markers as a guide, the depth and the lateral location of the target organ were determined by counting the locator grid squares in relationship to the locator grid markers (Figure 2.91). A bone marrow biopsy aspiration needle was used to create the percutaneous route to the target organ identified by the grid markers. Once the route was

Figure 2.91  Radiograph showing locator grid markers used to locate target organ.

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Figure 2.92  Coaxial needle in place using locator grid as a guide.

established, a coaxial percutaneous biopsy needle was placed at the depth and lateral position established using the grid markers (Figure 2.92). Radiographs were repeated to ensure biopsy needle location in relation to the target organ. The AP and lateral radiographs (Figures 2.93 and 2.94) demonstrate that the location of the target organ using marked locator grids for triangulation was readily accomplished. The drawing in Figure 2.95 demonstrates the triangulation and target location method in the axial plane. The use of the locator grid system with standard radiography appears to hold promise in the target organ identification and subsequent biopsy in field settings. Key features of the locator grid include making sure the system is adjustable to accommodate varied morphologic configurations and stabilization of the system to ensure that right angles are easily produced and maintained. The triangulation method using the locator grid with standard radiography may prove to be a useful field approach to precise tissue- or organ-targeted biopsies. The ability to conduct such biopsies in the field helps preserve the context and eliminates the risks associated with transporting those remains to an advanced imaging facility. Continued research needs to be conducted using smaller targets to assess the precision of this field technique. Cultural Practices Ancient Medical Practices  Ancient cultures appear to be fairly sophisticated in their medical practices. In the case of the Inca and other populations as well, trephinations were performed with great skill and with a remarkable success rate. It has been determined that among the Inca, based on new bone growth at the procedure site, trephination survival approached an 80% success rate (Verano 2003). Conventional radiography can be used to demonstrate not only the frequency of the medical practice of trephination but also the degree of success as determined by new bone growth at the site (Figure 2.96).

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Figure 2.93  AP radiograph showing coaxial needle in place at target organ.

Cultural Cranial Modification  What follows is a description of the practice of cultural cranial modification and the contribution made by conventional radiography not only to the recognition of its presence but also to the recognition of the biological impact of the modification practice. Background  Cultural cranial modification (CCM) can be defined as the intentional manipulation of the developing crania of infants to reshape the skull. CCM is accomplished through various cranial binding methods, which range in duration from weeks to years. The biological change that results from CCM procedures remains fixed over the life course of the individual. CCM has been practiced by many cultures throughout the world. CCM Variations Annular reshaping. It is the result of circumferential binding of the crania. This binding creates a decrease in cranial breadth and an increase in cranial length (Figure  2.97). Within this classification are three common variations: conical, tubular, and elongated.

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Figure 2.94  Lateral radiograph showing coaxial needle in place at target organ.

Figure 2.95  Triangulation and target location shown in a CT axial plane.

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Figure 2.96  Healing trephination clearly seen in the skull on the right.

Tabular reshaping. It is the result of an AP compression of the crania. Tabular reshaping results in an increase in cranial breadth, which is in contrast to the annular variation (Figure 2.98). The Impact of CCM  Biological effects: A wide variety of biological effects of CCM have been reported. There appears to be a relationship between CCM and a change in wormian bone frequency (Koningsberg et al. 1993; O’Laughlin 2004). Variations in suture

Figure 2.97  Radiograph of annular cultural cranial modification (CCM).

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Figure 2.98  Photograph of tabular cultural cranial modification.

configuration and complexity have also been reported (Gottlieb 1978; Blom 1999). Additionally there appears to be a correlation with the development of porotic hyperostosis (White 1996). Pressure necrosis in the occipital region has also been reported (Dietz and Bergfield 2001). There have been conflicting reports regarding the impact of CCM on vascular changes. One study using virtual endocasts made from CT scans of modified Mayan skulls demonstrated minimal effect on blood vessel foramina (MacLellan 2006). Another study reports a redirection of sinuses and meningeal vessel paths as they adapt to the new cranial vault shape (O’Laughlin 1996). Pathological effects: CCM has also been associated with craniosynostosis (White 1996). Craniosynostosis is a premature fusion of one or more of the cranial sutures. A single suture fusion is referred to as a simple craniosynostosis. Compound craniosynostosis involves two or more sutures. The cranial bones are well developed by the fifth gestational month in normal fetal development. After birth, the anterior fontanel closes around the age of 20 months. The posterior fontanel normally closes around 3 months. Mature suture closure is seen at about 12 years of age, with complete suture fusion occurring in the third decade and beyond. Craniosynostosis has many clinical implications for the afflicted individual. If it is simple craniosynostosis, the impact is largely cosmetic in nature. Compound craniosynostosis, on the other hand, presents with more grave clinical implications. Compound craniosynostosis carries an increased risk of elevated intracranial pressure when associated with bilateral coronal suture involvement. Further, it may also lead to anomalies of venous drainage. Compound craniosynostosis may also lead to a hypoplastic maxilla, resulting in upper airway problems and shallow orbits resulting in ophthalmologic conditions. Diagnosis of craniosynostosis includes radiography using AP or PA, a lateral, and, if possible, a Towne’s projection. In normal cranial flat bone development, radiographically the sutures appear as serrated, nonlinear lines, while with craniosynostosis suture markings appear as linear or are absent with early fontanel closure. Additionally, a skull radiograph

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Figure 2.99  Extensive annular cultural cranial modification in this child mummy in Cuzco,

Peru.

showing a beaten copper appearance associated with craniosynostosis indicates an increase in intracranial pressure, which may lead to other issues of vascular status and integrity. Two Subadult Case Studies of CCM Impact  Here are two case studies that demonstrate the utility of conventional field radiography in the detection of the biological impact of cultural practices such as CCM (Guillen et al. 2007). Case #1. The first case is that of an infant mummy under two years of age, likely Incan in origin, in Cuzco, Peru. The mummy presented with obvious annular CCM, demonstrated by major elongation of the skull (Figure 2.99). Lateral radiograph revealed fused coronal sutures (Figure  2.100). To further document suture fusion patterns, a modified Towne’s projection was obtained (Figure 2.101). The resulting radiograph demonstrates the

Figure 2.100  Lateral radiograph. Note fused coronal sutures.

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Figure 2.101  Direction of x-ray for a modified Towne’s projection.

fused sagittal suture patterns as well as the completely closed fontanels (Figure 2.102). The fused linear suture patterns and the closed fontanels demonstrate craniosynostosis in this infant mummy exhibiting annular CCM. There are a variety of clinical disorders associated with premature suture fusion. They include hypothyroidism, hypophosphatemia, hypercalcemia, vitamin D deficiency, severe constriction in utero, and positional molding (a type of cranial modification).

Figure 2.102  Radiograph from the modified Towne’s projection showing a fused sagittal suture and closed fontanels.

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Figure 2.103  Wrapped Chiribaya child mummy bundle.

The fused linear suture patterns and the closed fontanels demonstrate craniosynostosis in this less than 2-year-old infant mummy exhibiting annular CCM. It is beyond the scope of the study conducted to rule out the varied differential diagnoses. Although we cannot reliably determine the cause of death, it is reasonable to assume that the CCM, along with the craniosynostosis and its associated clinical disorders, may have contributed to this child’s morbidity or mortality. Case #2. The second case presentation is that of a wrapped infant mummy of the Chiribaya culture at the Centro Mallqui research facility, El Algarrobal, Osmore River Valley, near Ilo, Peru (Figure 2.103). A radiograph taken of the mummy bundle demonstrates an infant with annular CCM (Figure 2.104). An endoscopic route of entry was found on the posterior surface of the mummy bundle near the base of the skull. The endoscope was introduced and manipulated into the cranial vault. The endoscopic image revealed a mottled endocranial surface in the location of the cranial venous sinuses, which was deep reddish brown in color (Figure 2.105). The mottled endocranial surface suggests an increased intracranial pressure may have been present. The presence of residual darkened substance associated with the mottled surface suggests possible clotted, dried blood. This is suggestive of premortem intracranial hematoma. There are a variety of clinical disorders associated with increased intracranial pressures. They include generalized brain swelling, which in turn may lead to acute hepatic failure, ischemia, pseudotumor development, hypersensitivity encephalopathy, hypercarbia, Reye’s hepatocerebral syndrome, and decreased cerebral perfusion pressure. Also associated with increased intracranial pressure is increased venous pressure leading to possible venous thrombosis and obstruction of superior mediastinal or jugular veins. Obstruction to cerebral spinal fluid flow with or without absorption may lead to hydrocephalus, extensive meningeal disease, and obstruction of cerebral complex or superior sagittal sinus flow. Of particular interest is what is called the mass effect associated with increased intracranial pressure. This mass effect may lead to cerebral infarct with edema, subdural or epidural hematoma, and abscess or tumor formation.

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Figure 2.104  Radiograph showing extensive annular cranial modification.

The clinical picture of an individual afflicted with increased intracranial pressure includes headache, nausea, vomiting, papillary edema, papillary dilation, and poor sensorium. Given the radiographic and endoscopic data, this subadult (<6 years) with annular CCM may have been afflicted with increased intracranial pressures associated with a possible intracranial hematoma. Although we cannot reliably determine the cause of death, it is reasonable to assume that the annular CCM and its associated clinical disorders may have contributed to this child’s morbidity or mortality. Conclusions  Cultural cranial modification (CCM) may contribute to the increased morbidity and mortality of affected subadult individuals, particularly if CCM is extreme, demonstrated here in terms of craniosynostosis and increased ICP. It could also include other associated biological effects, such as porotic hyperostosis, cranial necrosis, and neurovascular changes. Additionally, there is an increased probability of CCM affecting morbidity or mortality if it is associated with preexisting conditions. Accurate description of form and degree of CCM without needing to unwrap valuable mummy bundles requires nondestructive multimodal paleoimaging techniques. On-site field

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Figure 2.105  Endoscopic view of possible dried blood (darken areas), possibly resulting from a premortem intracranial hematoma.

analysis requires the use of mobile imaging instrumentation such as endoscopy and radiography with appropriate positioning to attain desired and diagnostic data. The integration of multiple imaging modalities increases the descriptive/diagnostic potential of collected data. Future application of spectroscopic reflectance may confirm the presence of dried blood in cases where hematoma is suspected without needing to extract a sample. Burial Practices: Artifact Analysis  Another cultural practice is the manner in which the individual is interred. More specifically, in addition to the burial style, artifacts are often found within a mummy bundle or within the mummy itself. Some examples of these objects include metallic and nonmetallic offerings placed in the oral cavity, ceramics placed with the mummy or within body cavities, headpieces and jewelry fashioned from metal, shells, or textiles, special textiles, pouches, feather or cottonlike padding, medallions, and text written on paper. Conventional radiographs can detect these artifacts and help determine their location. As in all cases of radiographic application, more than one view is required to determine whether or not the object is on the outside or the inside of the mummy. In the case of artifacts with low density, exposure factors, specifically kVp, must be lowered in order to visualize the artifacts; this will be discussed in greater detail in Section III, “Artifact Analysis.” Mummification Method  Cultural practices dictate the mummification method used by a particular group or population. These methods may change over time as well. Perhaps one of the most familiar mummification practices is that of brain removal among Egyptian mummies. Conventional radiographs can determine if the cribriform plate of the ethmoid bone has been displaced to remove the brain of Egyptian mummies. Although the most common route for brain removal appears to be through the ethmoid bone, it wasn’t the only route. The superior portion of the orbit or eye socket was another route, radiographically documented, for brain removal. A careful radiographic examination of the entire cranial vault is a critical part of a standardized radiographic survey and will be discussed in greater detail in Chapter 5 of this book.

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In the case of Egyptian mummies, organ packets were often placed back into the body after they were desiccated outside the corpse. Radiographs, particularly nonscreen images, can often detect the presence of organ packets within body cavities (see Figures 2.4A and 2.4B). In addition, the use of resin throughout the body can readily be demonstrated even with images obtained with intensifying screens. One method of determining if the mummy was artificially prepared or naturally desiccated is to assess the remains for evidence of organ removal. Recall that the conventional radiograph may not show low-density organ remnants, leading to the assumption that the organs were removed and that artificial preparation was employed. Whenever possible, conventional radiography should be complemented by endoscopy, which may be able to detect organ remnants not seen by radiograph, altering the interpretation of the method of mummification. In many cases, the mummified body is held within an enclosure, such as a coffin, a bundle, or an urn. Conventional radiographs can determine the body position within the enclosure without having to disrupt the integrity of the container. In this manner, information collected by radiography can help one infer mummification and burial practices of the culture under investigation. The nature of the enclosure also may add to the understanding of how mummification was accomplished, particularly if the enclosure amplified the desiccation process. Temporal Context A more in-depth discussion regarding the application of conventional radiography to locate artifacts within the mummified remains will appear later in this text. Since it is particularly useful in dating modern mummified remains, only a brief consideration of the use of artifacts to identify temporal context will be presented here. The artifact may be a religious medallion, a dated coin, a pin, a coffin nail, or clothing. As an example, one case in which conventional radiography contributed to the determination of the temporal context is that of the mummified remains of a Chinese immigrant found in Nevada. A radiograph demonstrated what appeared to be a rivet in the crotch area of a pair of Levi denim jeans the individual was wearing at the time he was buried (Figure 2.106). Once the

Figure 2.106  AP radiograph showing the crotch rivet on this Chinese immigrant mummy. Pictured also is an endoscopic image of the rivet and a photo of a modern rivet.

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artifact was removed and it was conclusively identified as a crotch rivet, it was a matter of finding out the time frame crotch rivets were used in the manufacture of Levi denim jeans. The crotch rivet was discontinued because it was rumored to heat up while wranglers sat around the campfire and … well … you get the picture. Levi, in keeping with its customers’ concerns, no longer manufactured its denim jeans with crotch rivets. The crotch rivet was first used in 1873. This information helped us determine the period associated with the mummy being studied and defined the lower limit for the year of burial. Mechanism of Death On rare occasions, radiographic data can suggest the mechanism of death. In the previously mentioned case of the Cook of Ra, the depressed basilar skull fracture demonstrated no evidence of bony healing (see Figure 2.82). The images were reviewed by the deputy chief medical examiner for the state of Connecticut, Dr. Edward McDonough. He indicated that the fracture appeared to have been created by a rectangular-shaped object and produced from a blow that was delivered from right to the left. The direction of blow suggested that the implement was likely wielded by a right-handed individual. Dr. McDonough concluded that the injury should be considered the mechanism of death. The mechanism of death was also determined in another case, but required advanced imaging and will therefore be presented in Chapter 3.

Summary and Future Applications Since its inception, conventional radiography has made considerable contribution to the fields of anthropology and archaeology. Given the portability of conventional radiography, the authors feel that it should be an integral part of the data collection arsenal of all field studies. The information derived from conventional radiography may be used not only to collect valuable anthropological data, but it can help direct the course of the study by demonstrating unexpected findings and suggest other imaging modalities. The additional paleoimaging methods of endoscopy and advanced imaging should be applied in consultation with conventional radiography data. Conventional radiography should only be conducted by a skilled paleoimager in order to increase efficiency of the study and to ensure the acquisition of all potential information from the mummified remains or artifacts. Further, field radiography studies should be objective driven. Specialists trained in the methods and approaches to field radiography need to be developed. Specific procedural and application standards for conventional radiography should be adhered to and will be presented in Chapter 5.

References An Unwanted Mummy. 2001. The Mummy Road Show. New York: Engel Brothers Media. Aufderheide, A. C. 2003a. The Scientiἀc Study of Mummies. 515. Cambridge, U.K.: Cambridge University Press. Aufderheide, A. C. 2003b. The Scientiἀc Study of Mummies. 16. Cambridge, U.K.: Cambridge University Press. Beckett, R., J. Posh, C. Czaplinski, G. Conlogue, L. Quarino, J. Kishbaugh, and A. Bonner. 2008. Moving Toward Field Application of Percutaneous Needle Biopsy in Mummified Remains Using a Non-Gravity Dependent Needle Scrape/Aspiration Technique with CT and Endoscopic

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Guidance—A Preliminary Study. Paper presented at the 35th Annual North American Paleopathology Association Meeting, April, in Columbus, Ohio. Blom, D. E. 1999. Tiwanaku regional interaction and social identity: A bioarchaeological approach. Ph.D. dissertation, Anthropology, University of Chicago. Böni, T., F. J. Rühli, and R. K. Chhem. 2004. History of Paleoradiology: Early Published Literature: 1891–1921. JACR 55(4): 203–210. Bravo, A. J., G. J. Conlogue, and S. Guillén. Dead Men Walking: A Radiographic Survey of Spinal Pathology in Peruvian Chachapoya Mummies. 2001. Paper presented at the 87th Scientific Assembly and Annual Meeting of the Radiological Society of North America in Chicago, Illinois. Bravo, A. J., G. Conlogue, R. Beckett, A. Staskiewicz, L. Engel, and S. McGann. 2003. A Paleopathological Examination of Eighteen Mummies from the Church of the Dead, Urbania, Italy. Paper presented at the 30th Annual Meeting of the Paleopathology Association in Tempe, Arizona. Buikstra, J. E. and L. A. Beck. 2006. Bioarchaeology: The Contextual Analysis of Human Remains. London:Academic Press/Elsevier. Bushberg, J. T., J. A. Seibert, E. M. Leidholdt Jr., J. M. Boone. 2002. The Essential Physics of Medical Imaging. 2nd ed. Philadelphia: Lippincott Williams & Wilkins. Bushong, S. C. 2008a. Radiologic Science for Technologists. 9th ed. St. Louis: Elsevier Mosby. Bushong, S. C. 2008b. Radiologic Science for Technologists. 9th ed. 275. St. Louis: Elsevier Mosby. Bushong, S. C. 2008c. Radiologic Science for Technologists. 9th ed. 208. St. Louis: Elsevier Mosby. Bushong, S. C. 2004a. Radiologic Science for Technologists. 8th ed. 181. St. Louis: Elsevier Mosby. Bushong, S. C. 2004b. Radiologic Science for Technologists. 8th ed. 319. St. Louis: Elsevier Mosby. Cahoon, J. B. 1965a. Formulating X-Ray Techniques. 6th ed. 80. Durham, NC: Duke University Press. Cahoon, J. B. 1965b. Formulating X-Ray Techniques. 6th ed. 79. Durham, NC: Duke University Press. Carlton, R. R. and A. M. Adler. 1992. Principles of Radiographic Imaging. 590. Albany, NY: Delmar Pub. Inc. Cartmell, L., G. Conlogue, R. Beckett, and L. Engel. 2002. An Imaging Examination of the Legend of Hazel Farris. Paper presented at the 29th Annual Meeting of the Paleopathology Association in Buffalo, New York. Cave Mummies of the Philippines. 2002. The Mummy Road Show. New York: Engel Brothers Media. Chhem, R. K. and D. R. Brothwell. 2008a. PaleoRadiology: Imaging Mummies and Fossils. 15. Berlin: Springer-Verlag. Chhem, R. K. and D. R. Brothwell. 2008b. PaleoRadiology: Imaging Mummies and Fossils. 2–12. Berlin: Springer-Verlag. Conlogue, G., A. Nelson, and S. Guillén. 2004. The application of radiography to field studies in physical anthropology. JACR 55(4): 254–257. Conlogue, G. J., M. Schlenk, F. Cerrone, and J. A. Ogden. 1989. Dr. Liedy’s soap lady: Imaging the past. Radiologic Technol, 60: 411–415. Conlogue, G. and A Nelson. 1999. Polaroid imaging at an archaeological site in Peru. Radiologic Technol, 70(3): 244–250. Death in a Bog. 2002. The Mummy Road Show. New York: Engel Brothers Media. Dietz, M. J. and R. A. Bergfield. 2001. Deterioration of health and early agricultural dependence in southern coastal Peru. Paper presented at the Annual Meeting of the American Association of Physical Anthropologists, March in USA. Eisenberg, R. L. 1992a. Radiology: An Illustrated History. 25. St. Louis, Mo: Mosby-Year Book, Inc. Eisenberg, R. L. 1992b. Radiology: An Illustrated History. 95. St. Louis, Mo: Mosby-Year Book, Inc. Eisenberg, R. L. 1992c. Radiology: An Illustrated History. 79. St. Louis, Mo: Mosby-Year Book, Inc. Eisenberg, R. L. 1992d. Radiology: An Illustrated History. 79. St. Louis, Mo: Mosby-Year Book, Inc. Files, G. 1962a. Medical Radiographic Techniques, 2nd ed. 140. Springfield, IL: Charles C Thomas. Files, G. 1962b. Medical Radiographic Techniques, 2nd ed. 143. Springfield, IL: Charles C Thomas. Fornaciari, G., L. Ventura, G. Conlogue, R. Beckett, L. Engel, and A. Bucher. 2002. Paleopathology of a Nobleman from Popoli, Italy. Paper presented at the 29th Annual Meeting of the Paleopathology Association in Buffalo, New York.

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Frank, D. and P. W. Ballinger. 2003. Merrill’s Atlas of Radiographic Positions and Radiologic Procedures, 10th ed. 3 Volume set. New York: Elsevier Science. Gagliardi, R. A. (exec. ed.) and B. L. McClennan (ed.). 1996a. A History of the Radiological Sciences. 88. Reston, VA: Radiology Centennial, Inc. Gagliardi, R. A. (exec. ed.) and B. L. McClennan (ed.). 1996b. A History of the Radiological Sciences. 92. Reston, VA: Radiology Centennial, Inc. Gagliardi, R. A. (exec. ed.) and B. L. McClennan (ed.). 1996c. A History of the Radiological Sciences. 326. Reston, VA: Radiology Centennial, Inc. Gallegos, A., J. L. Thompson, B. Arriaza, S. F. Chung, V. Cassman, G. Conlogue, and R. Beckett. 2002. Preliminary Analysis of a Naturally Mummified Chinese Immigrant from Carlin, Nevada. Paper presented at the 29th Annual Meeting of the Paleopathology Association in Buffalo, New York. Gottleib, K. 1978. Artificial cranial deformation and the increased complexity of the lambdoid suture. Am J Phys Anthropol, 48: 213–214. Harris, J. E. and K. R. Weeks. 1973. X-Raying the Pharaohs. New York: Charles Scribner’s Sons. House of Bundles. 2002. The Mummy Road Show. New York: Engel Brothers Media. Konigsberg, L. W., L. A. P. Kohn, and J. M. Cheverud. 1993, Cranial deformation and nonmetric trait variation. Am J Phys Anthropol, 90(1): 35–48. Lang, J. and A. Middleton. 1997. Radiography of Cultural Material. 120. Oxford: ButterworthHeinemann. Mama Mia Mummies. 2003. The Mummy Road Show. New York: Engel Brothers Media. MacLellan, E. 2006. New and improved? How does new technology measure up against traditional methods of endocast creation? Canadian Association for Physical Anthropology Newsletter, vol. 2006(1). Mummy Menagerie. 2003. The Mummy Road Show. New York: Engel Brothers Media. O’Laughlin, V. D. 1996. Comparative endocranial vascular changes due to craniosynostosis and artificial cranial deformation. Am J Phys Anthropol, 101(3): 369–385. O’Laughlin, V. D. 2004. Effects of different kinds of cranial deformation on the incidence of wormian bones. Am J Phys Anthropol, 123: 146–155. Phalen, M. 1998. Personal communication. Polaroid Data Sheet T-804. a. Polaroid Data Sheet T-803. b. Princess Baby. 2002. The Mummy Road Show. New York: Engel Brothers Media. Redsicker, D. R. 2001. The Practical Methodology for Forensic Photography. 2nd ed. 12. Boca Raton, FL: CRC Press. Robbins, L. L. and E. H. Land. 1951. Application of the land method of film processing in Roentgenology. JAMA 1951(47): 244–250. Selman, J. 1985. The Fundamentals of X-Ray and Radium Physics. 470–472. Springfield, IL: Charles C Thomas. Tales of an Italian Crypt. 2001. The Mummy Road Show. New York: Engel Brothers Media. Verano, J. W. 2003. Trepanation in prehistoric South America: Geographic and temporal trends over 2000 years. In Trepanation: History, Discovery, Theory, eds. Arnott, R., S. Finger, and C. U. M. Smith, 223–236. Leiden: Swets and Zeitlinger. Walker, P. L. 2005. Greater sciatic notch morphology: Sex, age, and population differences. Am J Phys Ther (127): 385–391. White, C. D. 1996. Sutural effects of fronto-occipital cranial modification. Am J Phys Anthropol, 100(3): 397–410.

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Gerald Conlogue, Ronald Beckett, and John Posh Contents Introduction Computed Tomography or CT Scanning Background MDCT in Paleoimaging Disadvantages of CT Direct Digital and Computed Radiography Magnetic Resonance Imaging (MRI) Case Examples of MR Application to Mummified Remains Sabia James Penn Sylvester References

123 124 124 131 158 160 168 176 176 180 181 184

Introduction Although the primary focus of this book is paleoimaging in a field situation, the authors felt it necessary to provide a technical perspective of the computerized imaging modalities. At present, they may not constitute the first modality of choice, but there are certainly occasions when they will provide information that can be obtained in no other way. Computerized radiographic modalities are those imaging methods that utilize computer hardware to capture and store the data and software to manipulate, reorganize, and reconstruct data collected from imaging studies. There are two major categories of computerized modalities. The first is computed tomography (CT), which most people have become familiar with either through the popular media or as a patient or the relative of a patient. The second has to do with an effort to replace film with a digital image receptor (IR) as the recording media. There are two approaches in this category: computed radiography (CR) and direct digital radiography (DR; Fauber 2009). This chapter will present descriptions of these powerful imaging modalities, including a brief overview of the historical development, technological features, and the application potentials in the area of anthropological and archaeological research.

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Computed Tomography or CT Scanning Background The major disadvantage of conventional radiography during the first 60 years after its discovery was superimposition of shadows. Stereo-imaging techniques provided an illusion of depth but didn’t solve the problem. Beginning in 1921, work began to eliminate the superimposition problem with a technique initially termed body section radiography (BSR; Seeram 1985a). In 1935, Grossman introduced the term tomography, derived from the Greek word tomos, which means slice or section, and graphia meaning describing (Eiseberg 1992). The basis for this new technique was a coordinated motion between the x-ray tube and the image receptor. In the simplest motion, termed linear, the x-ray tube moved in an arch starting from the head end of the patient to the feet. At the same time, the image receptor moved, under the x-ray table, in the opposite direction (Figure 3.1). A plane within the patient parallel to the table was in focus, and all the anatomy above and below that plane was blurred and out of focus (Figure 3.2). This point at the center of the section, termed the fulcrum, constituted the pivot or plane of rotation of the x-ray tube and film (Seeram 1985b). To bring other planes into focus, the focal plane within the patient had to be raised or lowered. The thickness of the section was determined by several factors including the distance the x-ray tube traveled, termed amplitude, and the complexity of the x-ray tube movement. The greater the amplitude, the thinner the section visualized. Linear tomography provided the least complex motion and according to Hiss (1983), with an amplitude of 30°, a 2.12 mm section was demonstrated. If the angle were increased to 50°, the section thickness would be reduced to 1.19 mm. One of the disadvantages of linear tomography was that it produced streaks on the film. To eliminate the problem, more complex types of motion were developed. The thinnest slice, approximately 1.3 mm, was achieved with a motion term hypocycloidal, resembling “overlapping loops” and was employed for examinations of the inner ear (Figures 3.3A, 3.3B, and 3.3C). Although the modality became quickly accepted, there were a number of disadvantages. Since multiple levels within the patient would need to be imaged, at least four or five radiographs, termed tomographs or tomograms, were obtained from a particular region. Because A2

A1

Patient

Table

B1

B2

Figure 3.1  In linear tomography, the x-ray tube (A1) begins at the head of the x-ray table, and

the image receptor (B1) at the opposite end. By the end of the exposure, the x-ray tube (A 2) and the image receptor (B2) have reversed their positions.

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A2

A1

Section Thickness

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Figure 3.2  Above and below the axis of rotation, known as the fulcrum, is a region termed the section thickness that is in focus.

the x-ray source and image receptor were both moving, the area irradiated could not be as tightly restricted or collimated, as would be the case during a single exposure. Both these factors resulted in high radiation doses to the patient. In addition, the blurring of the anatomy above and below the focal plane made the images more difficult to interpret. In 1970, Electric & Musical Industries Ltd (EMI), England, achieved a monumental milestone in medical imaging. The company’s previous achievements included Enrico Caruos’s first recording in 1902 and establishing the Abbey Road recording studio of the Beatles. Godfrey Hounsfield, a physicist and engineer working at EMI laboratories, first demonstrated the modality that he originally called computerized transverse axial scanning (Seeram 2001). Allan Cormack, a South Africa-born medical physicist at Tufts University, Massachusetts, had earlier formulated the mathematics necessary to reconstruct the images. The impact of their work was so revolutionary that both shared the 1979 Nobel Peace Prize for their contributions to medicine and science. C

D

A

B

Figure 3.3A  A lateral radiograph of the head of a cat following an injection of contrast media

into the cerebral ventricles. Note the mandible (A), tympanic bulla (B), the olfactory bulb (C), and body (D) of the lateral ventricle.

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B

A

C

D

E

Figure 3.3B  A tomographic section of the cat’s head in a lateral position acquired with a hypocycloidal motion. Note that the olfactory bulb (A), body of the lateral ventricle (B), third ventricle (C), cerebral aqueduct (D), and fourth ventricle (E) were free from superimposition by the skeletal components of the skull. However, because the olfactory bulb and body of the lateral ventricle were slightly beyond the focal plane, both structures are somewhat blurred.

Since the modality incorporated a coordinated motion between the x-ray source and the image receptor, the term tomography applied. Instead of film, the image receptor was replaced by a detector that transmitted x-ray attenuation data to a computer. The x-ray tube and detector traveled over a 360° arch within a doughnut-shaped structure called the gantry. The patient was positioned on a table that moved into the gantry. The computer analyzed the attenuation profiles collected from a number of angles around the patient, mathematically superimposed the profiles, and generated an image of the patient’s anatomy. Since all the data were collected from the axial plane of the patient, the new modality was eventually called computed axial tomography or a CAT scan.

B

A

Figure 3.3C  With the focal plane moved more laterally, the olfactory bulb (A) is more clearly

defined. Air bubbles (B) in the contrast media within the body of the lateral ventricle indicate the structure was included in the section thickness.

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Due to the limited computational capacity of computers at the time, the first clinical CT scanners were small and restricted to imaging of the head only. These early units were in use between 1974 and 1976 and rapidly changed medical imaging procedures. The impact within radiology was so dramatic that immense pressure was exerted on manufacturers to develop units that wouldn’t be restricted to the head. Subsequently, “whole-body” systems became available by 1976, and CT became widely available by about 1980. There are now thousands of CT scanners, not only in the United States but worldwide. The first CT scanner developed by Hounsfield in his EMI laboratory took several hours to acquire the raw data for a single scan or “slice,” and took days to reconstruct a single 80 × 80 matrix image from this raw data. The latest multislice CT systems can collect up to 64 slices of data in about 350 ms, and reconstruct a 512 × 512 matrix image from millions of data points in less than a second. An entire chest can be scanned in 5–10 s using a modern multislice CT system. A more thorough consideration of the development and history of the modality can be found in Bushong (Bushong 2004); however, the major advantages and disadvantages relative to our discussion will be considered here. The advantages were tremendous. Because the images were reconstructed in an axial plane, superimposition was completely eliminated. Since the patient was in or close to the center of the x-ray tube-detector rotation, called the isocenter, magnification and distortion were eliminated, making it possible to take direct measurements from the images. Due to the inherent construction, the x-ray beam leaving the source was tightly collimated, minimizing scatter radiation so much that soft tissue structure could now be visualized. With CAT scans, it was not only possible to detect brain tissue within the skull but also to differentiate the gray matter from the white matter of the brain. Although the aforementioned advantages were significant advancements in medical imaging, this new modality was also quantitative. Up to this point, radiography was qualitative. Although there were attempts to quantify the images using standards of known density, all were subjected to the variability inherent to film processing. A difference of a few degrees in the developer temperature, a variation in the concentration of developer, improper fixation or washing, to name a few, would result in different density values. In addition, superimposition of shadows, such as gas or feces in the intestine lying over the vertebrae, would also provide different density values. This new modality eliminated these problems. To construct the axial image, the computer calculates what is termed the linear attenuation coefficient, or lac. Since x-ray attenuation is dependent on the penetrating power of the x-ray beam, determined by the kVp setting, the lac for each pixel or picture element of the image must be adjusted. For this process, the pixel lac value is standardized to the lac of distilled water at a specific kVp setting. This standardized pixel lac in turn is used to calculate the “CT number.” Each type of tissue or material will attenuate or absorb radiation differently, allowing for a tissue characterization and, therefore, a unique CT number. With distilled water as a standard, the CT number of water is 0. Regardless of the manufacturer and kVp setting, the CT numbers for specific tissue types are approximately the same; for example, the CT number for white matter is 30 and that for gray matter is 38 (Wolbarst 1993). Postprocessing also permits the contrast and density of the image to be adjusted through an operation termed windowing. The CT number of the tissue of interest is selected as the level, or center, of a particular window of values to be displayed. The window width

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Figure 3.4A  An axial section through the skull at the level of the third ventricle with a narrow window width (WW) of 100 provided visualization of cerebral structures.

indicates the range of CT numbers displayed as one of 256 shades of gray. Any CT numbers to the left of the window will appear “black” on the image and those to the right of the selected values will appear “white.” A narrower window, for example, one with a window width (WW) of 100, is utilized to differentiate tissues of similar density, such as gray matter (CT # = 38) and white matter (CT # = 30) of the brain. With a window width of 100, each CT number is separated by 2.56 shades of gray. Since the tissues are separated by only 5 CT numbers, at WW = 100, there are 12.8 shades (2.56 × 5 = 12.8) separating the tissues, enabling easy differentiation (Figure 3.4A). Wider windows, for example, WW of 500, are employed to suppress differentiation of subtle differences in tissue density, such as “eliminating” brain tissue entirely to permit an evaluation of the cranial bones (Figure 3.4B). Until the mid-1990s, all CAT data were collected by a process called slice-by-slice acquisition. After each axial slice was collected, the table on which the patient was lying would move cranially or forward for a prescribed distance. Another slice would then be collected, and the process would continue until all the desired anatomy was scanned. If sagittal or coronal sections were required, a postprocessing operation, called reformatting, would stack all individual slices previously collected and “cut” them into the desired plane. There are several disadvantages to this procedure, but only the one relevant to this discussion will be considered here. Since the time between individual slices might be several seconds, the patient or their organs would probably be in a different location. The reformatted images would not show a smooth continuity along the edges of organs or structures (Figure 3.5).

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Figure 3.4B  An axial section at the same level as that in Figure 3.4A, but with moderate WW of 500. Note that only the skeletal components of the calvarium were visualized.

A

B

Figure 3.5  The axial image A indicates the level (dotted line) that was used to produce the sagittal reconstruction.

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A

Figure 3.6  A three-dimensional reconstruction from a study done in the mid-1980s. Note the irregular margin of the right orbit (A) created by the stacking of the axial slices.

This problem was also noticeable in cases where three-dimensional (3D) reconstruction was desired (Figure 3.6). The problem was solved when a new approach to data collection was introduced. Due to a technical innovation, known as slip ring technology, the x-ray tube and detectors could continuously rotate around the patient as the table constantly moved forward. The result was that instead of individual slices, a volume of anatomy was acquired. Since the volume could be postprocessed into any plane, the modality became known as simply CT. The more accurate description for the new generation of scanners incorporating this technical advancement is spiral or helical CT. The introduction of helical CT has greatly advanced the progress of medical imaging. Scans of a region of anatomy, such as the chest, can be accomplished in “one breath-hold” of the patient. At the time of this writing, the equipment is capable of collecting the equivalent of 64 0.5-mm-thick slices during one scan. Since the units can have multiple detectors collecting data during an interval, they are also called multidetector or MDCT. In addition, software has been developed to perform specialized postprocessing operations. Algorithms designed for specific anatomical regions of a living patient have eliminated the need for technologists to manipulate variable settings on the scanner. Manufacturers are anticipating the future needs of the medical imaging community, and are introducing not only software but also hardware updates more rapidly. The impetus is to reduce the time required to image a patient while acquiring the greatest amount of information. All this innovation comes at a high cost. A 64-slice CT scanner can cost $850,000–$950,000. Once the unit is purchased, the costs do not end. The accompanying service or maintenance contract, which also includes software updates, can add another up to $120,000 in costs per year. The continuous output of the x-ray tube during the MDCT scan generates a tremendous heat load for the tube to overcome. In a busy imaging department that operates 24 h a day, 7 days a week, the x-ray tube probably will not last a year. Without the service contract, the cost of a replacement tube could exceed $80,000.

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MDCT in Paleoimaging Although the newest equipment can produce remarkable images on living patients, it is not necessarily well suited for the examination of mummified or skeletal remains. The first obstacle would be access to the equipment. Few imaging facilities can provide repeated access to the extremely expensive equipment. Therefore, specific imaging questions must be defined before an examination is undertaken. If the entire length of a 60 in. (152 cm) mummy was going to be scanned at 0.5-mm-thick slices, that would result in 3048 images! Not only would it be very time consuming to examine each image thoroughly, it would also require a tremendous amount of computer memory to store the data. In addition, it would certainly decrease the life of the x-ray tube. A better approach would be to employ conventional radiography to locate those regions of particular interest and scan only those areas at higher resolution with thinner slices. The other, and possibly greater, problem with the newer units would be finding a technologist to operate the unit. As previously mentioned, MDCT units have specific algorithms that have been incorporated into the software based on average-size living humans. Unfortunately, the manufacturers have not included a mummified tissue algorithm. Therefore, a specific volume of the mummy may be collected in a few seconds; however, locating and applying an appropriate algorithm from the available choices may take considerable time. This is most evident when 3D reconstructions are desired. In the living patient, if an examination of the skull calls for a 3D reconstruction of the calvarium, the completed image will include all of the skeletal components with the elimination of all soft tissue elements such as skin, muscle, and brain. Since even the thinnest components of the skull are hydrated and have adjacent soft tissue structures, the reconstruction software is programmed to recognize them, and they will be included in the 3D image. Unfortunately, this isn’t the case with mummified or skeletal remains. The problem is clearly demonstrated in a mummy examined in 2000. Although the bone seems “thin,” the temporal regions of the skull and humeral head of the left shoulder of the remains are clearly visible on conventional radiographs (Figure 3.7). However, on the 3D CT image, the same regions of the skull appear as “holes” (Figure 3.8), and the entire surface of the humeral head appears to be “missing” (Figures 3.9A and 3.9B). When the bone algorithm was applied during the 3D reconstruction, the lower CT numbers from the “thin” areas were omitted from the reconstruction data set. Prior to the advent of the newer CT units, it would have been possible to manually input the CT numbers that would be included in the reconstruction. Therefore, before undertaking a CT study, the specific objectives for using the advanced modality must be determined. Elimination of superimposition that prevents an interpretation on the conventional radiographs certainly is justification for a CT examination. A mummy known as Andy provides an excellent example. He was a sideshow mummy that the Ripley’s Believe It or Not organization was planning to include in a new museum opening in New Orleans, Louisiana. The initial anterior-posterior (AP) and lateral radiographs of the chest suggested rib and possibly sternal fractures (Figures 3.10A and 3.10B). Axial CT images clearly demonstrated rib fractures. In addition, the soft tissue structures of the thorax, the lungs and heart, were shifted to the right. In conjunction with the rib fractures, the shift of the organs strongly suggested the individual suffered a tension pneumothorax that led to his death (Figure 3.11).

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Figure 3.7  Lateral radiograph of the skull and left shoulder of a mummy examined in 2000.

Another advantage of CT is the modality’s ability to demonstrate soft tissue that would otherwise not be seen on conventional radiographs. This was demonstrated in a mummy known by several names including James Penn, Stoneman, and Stoneman Willie (Figure  3.15). The story surrounding the individual, who resides in a funeral home in Pennsylvania, indicates that he died in 1895. The body was embalmed with formalin and, because relatives never claimed the remains, the body still resides there. The radiographs of

Figure 3.8  Areas where the skull was relatively thin appear as holes in the three-dimensional reconstruction. The entire head of the humerus was also dropped from the reconstruction.

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Figure 3.9A  A conventional radiograph of the left shoulder of the mummy. Note the thin cortex (arrow) of the humeral head.

his skull, chest, and abdomen reveal organs that were in an excellent state of preservation. Other than foreign bodies in his mouth, nothing irregular was noted. The foreign bodies removed under endoscopic guidance turned out to be pennies that probably were deposited as “offerings” while the body had been at the funeral home. In addition, a nail was also recovered from under the tongue, but its significance could not be determined. Since the organs were in such an exceptional state of preservation, it was hoped that a CT examination would contribute information regarding the health status of the individual

Figure 3.9B  On the three-dimensional reconstruction, the entire humeral head (arrow) appeared to be fragmented.

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Figure 3.10A  A lateral Polaroid image of the upper portion of Andy’s chest demonstrating an apparent fracture of the sternum (arrow).

prior to his death. Axial images of the lungs revealed adhesions that suggested an ongoing, active, infectious process at the time of the individual’s death, possibly tuberculosis. Pulmonary lymph node lesions were also seen (Figure 3.12). Since the images were collected as a “volume” instead of “slice by slice,” the volume was “reconstructed” into a coronal plane by a process called reformatting and demonstrated the adhesions in that plane (Figure 3.13). Incorporated into all CT units is the ability to characterize tissue by CT numbers. A software function, termed region of interest (ROI), allows the CT number for a specific region of the image to be calculated. Using the cursor, an ROI in the shape of a circle or ellipse can be placed anywhere on the image. The computer will calculate the linear attenuation coefficient and the subsequent CT number for each pixel within the ROI. The display following completion of the data manipulation will calculate the area of the drawn ROI, the number of pixels included in that area, the average CT number, and the standard deviation of CT numbers (Figure 3.14). If there is a large standard deviation, such as that seen in ROI2, then there are probably several types of tissues with different densities, in this case bone and cartilage, included in the ROI. Therefore, for the most accurate data, the ROI deviation should not be too large. In both ROIs 1 and 2, the standard deviations were small. The ROI may be applied to mummified remains and artifacts as well (Figure  3.15). Since few ROIs have been collected from organs or materials, such as resin (Figure 3.16) within mummified remains, at this time the exact significance of these data are not known. However, they can be compared to CT numbers from comparable living tissues to possibly

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Figure 3.10B  A lateral image of the lower portion of Andy’s chest clearly showing the heart shadow (black arrows) and what appears to be a fractured rib (white arrow).

explain the effects of different types of desiccation and preservation processes. For example, the CT number for gray matter ranges from 32 to 44 and white matter from 24 to 36 (Webster 1988). In Sylvester, who was embalmed with arsenic, the ROI within the brain had an M of 84 with an SD of 6.5 (Figure  3.17A). However, the ROI from the brain of George/Fred, embalmed with a formaldehyde-based embalming fluid, had an M of 76 but A

B

Figure 3.11  An axial image through the chest demonstrating a fractured rib (A) and a shift of the thoracic soft tissue structures to the right side of the chest cavity (B).

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Figure 3.12  An axial image through the apical region of the thorax demonstrating a lesion (arrow) in right lung.

an SD of 70 (Figure 3.17B). Although both mean CT number values were similar to each other, they were certainly higher than that of living brain tissue. In addition, the higher standard deviation noted in George/Fred indicated that there was considerable variation within the ROI. Until more research is conducted in this area, the significance of the tissue values cannot be determined.

Figure 3.13  A coronal reconstruction of the chest showing an adhesion (arrow) between the right lung and thoracic cavity wall.

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Figure 3.14  An axial section through the abdomen of a patient illustrating the calculation of three regions of interest (ROIs). The first ROI was in a pocket of gas within the stomach. The mean value, M, was −874.4 with a standard deviation, SD, of 33.9. The second ROI (arrow), a bit difficult to clearly see on the image, encompassed the costal cartilage of the rib. This region had an M of 906.9 and SD of 303.5. The third ROI was located in the spleen and had an M of 55.0 and SD of 4.1.

The most valuable CT information is frequently obtained from sectional images. An example is from a sideshow mummy that can be found at Ye Old Curiosity Shop in Seattle, Washington. The mummy, known as Sylvester, has the required fantastic story that accompanies all remains that traveled on the sideshow circuit. After being caught cheating during a card game, he was supposedly shot in the abdomen. Somehow he made it out of the Arizona saloon, got on his horse, and escaped. Unfortunately, some miles into the desert he fell off the horse and died. According to the legend, mummification was accomplished by the desert sand and the dry Arizona climate. His extended body is propped up in a display cabinet with a small cloth covering his pelvic area. Above the cloth is a round opening with a red margin and a small sign indicating that the opening was the entrance of the fatal bullet. In 2001, a radiographic survey was conducted on the remains at the curiosity shop. The initial images revealed an incredible level of preservation of the brain, and all of the thoracic contents were easily identifiable. Soft tissue structures within the abdomen were obviously present, but few could be individually identified. There was no radiographic evidence of a bullet within the abdomen, and no exit wound was detected on the body. An endoscopic examination through the entrance wound did not reveal evidence of dried blood or damage to the underlying abdominal cavity structures (Figure 3.18). An unexpected finding on the AP and lateral projections of the skull was what appeared to be pellets from a shotgun wound to the right side of his face (Figures 3.19A and 3.19B). A visual inspection of the face did reveal a number of raised “bumps,” but provided no indication of what lay beneath (Figure 3.20). Obviously, the wound had occurred quite a while prior to the individual’s death since the bumps were well healed over.

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Figure 3.15  An axial section through the neck of James Penn aka Stoneman Willy showing three regions of interest (ROI). The first region, within the coins lodged in the oropharynx, had a mean value of 4000, the maximum value on the CT number scale. The second region was within the trachea. The CT number for air is –1000; however, the mean value for this region was −711.54, suggesting there was material, possibly dried mucus, in the section. The third region was located within the vertebral body and had a value of −76.68. The low value was due to the dehydration of tissue.

Therefore, two specific questions regarding Sylvester could possibly be answered using CT. First, was there evidence of a gunshot wound to the abdomen? And what are the precise placements of the pellets in the face? In 2007, a CT study was undertaken to address these questions. A GE MDCT was employed to collect the volume of the abdomen that included the gunshot wound. From that volume, axial, sagittal, and coronal sections through the wound were reconstructed (Figures 3.21A and 3.21B). No evidence of bleeding or damage to the underlying abdominal structures was demonstrated. The measurement function was also utilized to determine the size of the opening in the abdomen. The dimension was obtained from each of the three planes, and revealed that it was approximately ¼ in. (0.64 cm) in diameter for each (Figures 3.22A, 3.22B, and 3.22C). If the wound had been premortem, there is little chance that it would be perfectly round. The dehydration process that was evident over the entire surface of the body would have altered the shape of the entrance wound. It appeared the opening was created postmortem to substantiate the legend. The pellets beneath the face proved a more interesting problem. The axial sections provided precise information as to the location of each pellet, none of which appeared to have penetrated the bone (Figure  3.23). Several pellets were located in the oropharynx (Figure  3.24). Since none of the pellets seemed to have sufficient force to penetrate very deeply, the sections suggest that his mouth must have been open at the time of the

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Figure 3.16  An axial section through the brain of the Egyptian mummy “PaIb” at the level of the temporal mandibular joint showing two ROIs in the resin. The layering of the resin indicated that there had been two pourings. The difference in the ROI mean values revealed that the composition of each layer was not identical. In both ROIs, the large SD value suggested that the materials in each layer were not homogeneous.

incident. For aesthetic reasons, a 3D reconstruction of the head was requested. The resulting images, obtained using a computed tomographic angiography (CTA) algorithm, were dramatic especially since the entire head could be rotated or tilted. However, the CTA algorithm automatically performed a function called smoothing when encountering the pellets. Each appeared to be more of a skin lesion rather than the location of a foreign body (Figure 3.25). Another advantage of the volumetric acquisition of CT data is the possibility of slicing that acquired volume in any desired plane. An excellent example was demonstrated in another mummy by what appeared to be a gunshot wound in the distal right femur just above the knee. The mummy, known as George/Fred, was a sideshow mummy that belonged to Ripley’s Believe It or Not organization. On the conventional radiographs, a defect was noted on the AP and lateral projections (Figures 3.26A and 3.26B), but it couldn’t be well visualized. The initial CT examination collected axial sections of the region and clearly demonstrated the wound as it progressed through 12 axial slices (Figure 3.27). An obvious entrance was noted on the medial aspect, and similarly an exit was seen on the lateral aspect. Evidence of healing was also observed at the entrance, suggesting some time had passed since the wound was acquired. Unfortunately, because the wound was diagonal, it was not seen in a single axial section over its entire path. The volume was reformatted to create a section in the axial, sagittal, and coronal planes so that each would be entirely

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Figure 3.17A  An axial section through the brain of Sylvester at the level above the ventricles. The mummy had been preserved with an arsenic-based embalming fluid. The ROI had a mean value of 84 and a standard deviation (SD) of 6.5. The small SD indicated that the materials within the oval have similar values.

Figure 3.17B  An axial section through the brain of George/Fred at the level above the lateral ventricles. The mummy had been preserved with a formaldehyde-based embalming fluid. The first ROI, oval 1, had a mean CT number of 76, but an SD of 70; the tissue values were more varied in this mummy. The material posterior to the cerebral hemispheres was probably dried embalming fluid and had a mean value of −502.

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Figure 3.18  Endoscopic view through the bullet hole, showing no interior anatomical damage.

Figure 3.19A  The lateral projection of Sylvester’s skull, demonstrating some of the shotgun pellets (arrows) embedded in the mummy’s face.

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Figure 3.19B  The AP projection of Sylvester’s skull film was intentionally underexposed to more clearly visualize the relationship between the shotgun pellets (arrows) and the skull.

through the wound (Figures 3.28A and 3.28B). The off-axis reformatting used in this case further demonstrates the application of CT scanning with specific objectives in mind. As previously mentioned, CT data can be complied in a manner so as to achieve a 3D image. But when is a 3D study necessary? An Egyptian mummy on display at the Barnum Museum in Bridgeport, Connecticut, provides an excellent example. A conventional radiographic examination was conducted at the museum. Once it was determined that the mummy was stable, it was transported by ambulance to a free-standing imaging center approximately 5 mi from the museum. Thin (0.6-mm-width) sections were collected of the head and pelvis. From the axial, sagittal, and coronal images, it was clear that the brain had not been removed by the traditional route, that is, through the cribriform plate as seen in some Egyptian mummies. Instead, the medial wall of the left orbit had been destroyed in order to access the cranial contents (Figure 3.29). A 3D image was desired to more dramatically demonstrate the defect. The technologist spent more than an hour applying various 3D algorithms until she achieved the desired results with the CTA algorithm (Figure 3.30). Application of 3D reconstruction was also employed to confirm the sex of the Barnum mummy. The hieroglyphs on the coffin indicated that the mummy was a male priest known as PaIb. The lateral radiograph of the skull suggested a female (Figure 3.31), and

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Figure 3.20  A photograph of the right side of Sylvester’s face, showing some of the raised bumps (arrows).

the 3D surface renderings of the genital area confirmed that the remains were not male (Figure 3.32). In addition to addressing specific questions, 3D reconstruction can be valuable for the aesthetic, nondiagnostic images that can be produced. The same technologist who spent so much time manipulating the PaIb images expended even more time trying to find the correct algorithm for the 3D reconstruction of an extended ibis mummy (Figure 3.33). The mummified bird and 3D images were incorporated into an Egyptian exhibit at the Ripley’s Believe It or Not Museum in New York City. Because of the sectional presentation of the images and the ability to accurately measure structures, CT-guided biopsies are commonly performed medical procedures. In general, the value of biopsy of tissues or organs from mummified human remains is well established. Tissue biopsies can be used to answer a variety of research questions designed to add scientific knowledge or paleopathological data to a case (Cockburn et al. 1998). Tissue biopsies may be used to determine if organs are present. Taphonomic impact may result in morphological changes, making organs indistinguishable from surrounding tissues. Biopsy can help determine if the tissue collected is, in fact, from a specific organ. Biopsy has been instrumental in detecting evidence of any paleopathological processes that are present in the remains. Biopsy tissue samples have been rehydrated for histological examination as well as both qualitative and quantitative elemental analysis

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Figure 3.21A  The axial section through the track of the hole (arrow) in the abdomen.

Figure 3.21B  The sagittal section through the track of the hole (arrow) in the abdomen.

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Figure 3.22A  The axial section demonstrating an identical measurement, 0.656 cm (0.258 in.), of the external and internal hole in the abdomen.

(Aufderheide 2003). A variety of tissues have proved useful in answering anthropological and paleopathological questions regarding mummified human remains. Hair, skin, muscle, various organs, and associated artifacts have all yielded substantial data for bioanthropological studies. There are several methods currently employed to attain biopsied material for analysis. All of these methods are destructive in that they remove material from the mummified remains, thereby altering the body or the anatomical context permanently. Among these, anatomical dissection (mummy autopsy) is the most reliable method of obtaining biopsies

Figure 3.22B  The sagittal section with a measurement, 0.586 cm (0.231 in.), of the hole in the

abdomen.

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Figure 3.22C  A measurement, 0.586 cm (0.231 in.), of the hole from one of the coronal sections.

that are from the correct anatomical target location and are of a volume that can yield the most data (Aufderheide 2003). Full anatomical dissection “disassembles” the remains and alters the original morphological context. It is important to note that the material resulting from such dissections does not disappear; rather, the material is appropriately

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Figure 3.23  An axial section through the skull demonstrating the precise position of one of the pellets (A) just beneath the skin. The excellent state of preservation is evident from the clearly discernable cerebellum (B).

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Figure 3.24  An axial section through the skull with a pellet (A) resting against the ramus of the right mandible and another (B) within the left oropharynx.

Figure 3.25  A 3D reconstruction demonstrating the position of the shotgun pellets. Some of the pellets have been identified with arrows.

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Figure 3.26A  The AP projection of George/Fred’s left knee with diagonal radiopaque line (arrows) that may be the margin of the hole through the distal femur.

stored for future scientific analysis. Short of a full autopsy, a target organ or tissue resection may be conducted as well, thus preserving the remainder of the mummified remains for future research. Another method of tissue biopsy is needle biopsy. This procedure may be conducted “blind” by using anatomical landmarks, or by using direct visualization with endoscopic techniques. Another great potential for site-specific tissue biopsy is seen in the computed tomography-guided percutaneous needle biopsy (CTPNB) method. This technique was reported in the case of an arsenic-embalmed sideshow mummy known as “Marie O’Day” (Conlogue et al. 2005; Figures 3.34A and 3.34B). The research employed a nongravity coaxial needle biopsy method without aspiration. Although the technique was well demonstrated, not enough tissue was extracted for analysis. Another study (Ruhli et al. 2002) reported the applicability of the CTPNB method to extract tissue adjacent to the vertebral spine. Using this method requires moving the mummified human remains to the center where the CT scanner is located, risking reorientation of internal structures during transit. The report also described a gravity-dependent approach to tissue collection through a bone aspiration biopsy needle. The gravity-dependent positioning is well suited for an imaging center setting, where the disruption of internal body context has already been altered. However, the method is not suited for field biopsy as a CT scanner is difficult

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Figure 3.26B  The lateral projection of the knee showing the radiolucent entry (A) and exit (B)

wounds.

Figure 3.27  An axial section demonstrating the entry wound on the medial aspect of the knee. The “C”-shaped structure within the wound (arrow) is an indication that healing had begun prior to death.

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Figure 3.28A  An off-axis axial section through the entire track of the wound.

and costly to transport to the field. The fact that many (not all) mummified remains in situ are interred in a horizontal orientation resting on the floor of an earthen tomb often within a burial coffin or in a seated position makes gravity-dependent biopsy impractical. We undertook a study to determine if tissue biopsy could be conducted in a non-gravity-dependent position. The research question was addressed by replicating the described CTPNB method, but substituting the gravity-dependent biopsy procedure with a nongravity-dependent needle scrape/aspiration technique modeled after the transthoracic needle aspiration biopsy employed in clinical medicine (Beckett et al. 2008). The subject of this study was George/Fred, a late 19th to early 20th century mummified male (described in Chapter 2). The mummy’s external and internal preservation was very good, making the subject an excellent choice for organ tissue biopsy. For this study, the liver was targeted for biopsy as its radiographic density indicated that the hepatic tissue was easily recognizable and accessible for biopsy.

Figure 3.28B  An off-axis coronal section through the entire track of the wound.

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Figure 3.29  Two coronal sections showing the destruction of the medial and superior wall of the left orbit (arrows).

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Figure 3.30  A 3D reconstruction from the interior perspective of the skull showing the route of brain extraction (A) and the mass of resin (B) in the occipital region.

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Figure 3.31  A sagittal section through PaIb’s skull showing the lack of a distinctive browridge

(arrow).

Figure 3.32  A 3D reconstruction of the pelvic region revealing what appears to be labia (arrows) and a lack of male genitalia.

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Figure 3.33  (A) A 3D reconstruction of an Egyptian ibis mummy in an extended position. Due to the reconstruction algorithm, the mummy’s wrappings have a reddish appearance. (B) A closer view of the body cavities with some of the wrapping removed by image manipulation.

A standard CT-guided percutaneous needle biopsy method was employed to determine if a needle scrape/aspiration technique would yield a useable sample. The subject was in a supine position. To assess the potential of a non-gravity-dependent tissue sampling method, biopsies were attempted from an anterior-lateral approach. A 14-gauge coaxial needle was introduced intercostally on the left side at approximately the anterior axillary line using the CT axial images to guide the needle introduction (Figure 3.35). Due to the durable nature of the mummified liver, the standard coaxial biopsy was unable to attain a sample. In fact, the tip of the coaxial needle was bent and rendered useless for the procedure (Figure  3.36). An 8-gauge bone marrow biopsy aspiration needle was introduced, again under CT guidance, to the intrahepatic region. The cutting inner cannula was removed leaving the outer cannula in place as a guide. A new coaxial needle

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Figure 3.34A  A prebiopsy axial image through the chest of Marie O’Day. The tip of the biopsy needle (A) was located just above the target (B), a calcification in the chest.

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Figure 3.34B  Following the biopsy attempt, the target (arrow) was still in place.

Figure 3.35  Percutaneous transthoracic needle biopsy with CT guidance on George/Fred.

Figure 3.36  Coaxial needle tip bent after biopsy attempt.

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Figure 3.37  Bone marrow aspiration needle in place with coaxial needle passing through the inner lumen under CT guidance.

was then inserted through the inner lumen of the bone marrow biopsy aspiration needle (Figure 3.37). Scrapings were made with the tip of the coaxial needle within the hepatic tissue. The coaxial biopsy needle was then removed from the inner lumen of the bone marrow biopsy aspiration needle. A series of syringes were then alternately leur-locked onto the proximal end of the bone marrow biopsy aspiration needle, and attempts were made to create a vacuum to draw tissue scrapings up through the cannula and into the syringe barrel. Syringe sizes included a 1 cc tuberculin syringe, a 20 cc syringe, and a 60 cc syringe, with each producing varying results (Figure 3.38). In addition to CT guidance and due to adequate access routes, the coaxial needle biopsy attempts and the bone marrow biopsy aspiration needle were placed under endoscopic visualization. The sample was sent to a trace elements laboratory for analysis. Once the bone marrow biopsy aspiration needle was in place, the different syringes yielded varying results. The 1 cc tuberculin syringe was unable to aspirate a sample. The 20 cc syringe was able to gather a scant sample, which appeared as brown flakes from the needle scraping. The 60 cc syringe was superior in aspirating a reasonable sample, which consisted of a larger volume of brown-colored flakes (Figure 3.39). Both the 20 cc and the 60 cc aspirate samples were then analyzed. The sample was analyzed at the Cedar Crest College trace evidence laboratory; the results of infrared analysis are displayed in Figures 3.40 and 3.41. The trace laboratory results indicated that sample #1 from the 20 cc syringe was of protein composition, possibly albumin, casein, gelatine, and trypsin. The major infrared peaks were seen at 1641, 1526, and 1237 cm−1. Analysis of sample #2 from the 60 cc syringe aspirate shows a chemical composition indicating adipose tissue and bis (1-methylheptyl) adipate, a fire ant repellent, with major IR peaks at 1724, 1454, 1233, and 1162 cm−1. Given the necessity of biopsy in many cases involving mummified human remains, it is critical to be able to accurately biopsy the target organ or tissue. CTPNB is clearly an excellent means of precise tissue biopsy. The study by Conlogue et al. (2005) using transthoracic percutaneous needle biopsy did not use gravity dependence or an aspirational technique, and, as a result, did not acquire a usable sample. The report by Ruhli et al. (2002) used CT guidance and gravity dependence and did collect a usable sample. If the remains have already been transported to an advanced imaging facility, the results of this study suggest that a non-gravity-dependent needle scrape/aspiration method may negate the need to manipulate the mummified remains in order to use a gravity-dependent biopsy approach. This, in turn, may reduce the potential for disruptions in the spatial relationships of the

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Figure 3.38  Various syringes used to apply vacuum following scraping. Top to bottom: 1 cc tuberculin (TB) syringe, 20 cc syringe, and 60 cc syringe.

internal context. Non-gravity-dependent percutaneous needle aspiration biopsy has been used extensively in clinical medicine, in particular, in lung needle aspiration biopsy procedures (Larscheid et al. 1998; Cox et al. 1999). In clinical medicine, the advantage of this procedure is that the target tissue is hydrated, and a more direct vacuum can be created during the aspiration process. In dried mummified tissue, however, the absence of hydrated

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Figure 3.39  Liver aspirate seen in a 60 cc syringe.

tissue necessitates the addition of a scraping maneuver and greater airflow generation to evacuate these tissue scrapings. The study results suggest that using a larger syringe (60 cc in this study) may produce a greater airflow and, therefore, a greater potential for sample acquisition in a non-gravity-dependent technique. This may be due, in part, to the degree of increased airflow created when the plunger of the syringe is drawn back at various rates. Based on the results of this study, it is not known if even a greater flow would result in a better sample. Further research including a standardized vacuum draw with a catch trap in-line would help address this question. In addition, the standardized vacuum system Liver Apirate Sample 1

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Figure 3.41  Infrared results for liver aspirate #2.

may allow for greater negative flow than could be developed from a syringe system. The authors would recommend using a clinical adjustable suction device to evacuate bodily secretions with a collection trap in-line in an attempt to quantify the vacuum required for sample acquisition. Researchers must also consider the quality of the preserved target organ, which would influence the ability to scrape tissue for aspiration. If the organ is very durable, less material may be released during the scraping procedure. In addition, the manner in which the material is scraped has additional implications for the obtainable sample. Terms related to scraping such as gentle, moderate, or vigorous need to be defined and standardized in future reports using this technique. With this said, the size of the sample obtained from the needle scrape/aspiration technique may also be a concern depending on the analyses desired. Since the sample is often scant, it would be difficult to say with any degree of certainty that a disease was or was not present in the sample. The fire ant repellent found in the sample was likely the result of fumigation efforts associated with the original warehouse location of this subject. The mummy was held for many years in Florida, which is well known for its fire ant population. This finding could have forensic implications under different circumstances. The results of this study suggest that the non-gravity-dependent percutaneous needle scrape/aspiration biopsy technique holds promise in preserving the internal context, given that the mummified remains do not need to be manipulated into a gravity-dependent position. Disadvantages of CT Perhaps the greatest disadvantage of CT scanning applications in anthropology and archaeology is the size of the equipment. CT scanners are most often fixed units within

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an imaging facility, and accessibility to scanning equipment can be problematic. Since CT scanners were designed to diagnose injury and disease in living people, patient imaging takes precedence over the examination of mummified remains. Getting time to use a scanner often necessitates working late at night or during a period when patients are not scheduled. There are dedicated research centers where a CT scanner may be available, but that is the exception. Another disadvantage is the potential cost of using the equipment. A center may charge a fee for scanner time to compensate for the tremendous operating costs previously discussed. Living patients can be scheduled on a 64-slice scanner every 5 or 10 min. The short interval is due to several factors. First, the precise region to be scanned within the patient is known. In addition, preset protocols eliminate the need for the technologist to spend a lot of time determining the technical factors required to scan the region requested. Without specific target regions within a mummy, the CT examination can take an hour or more, the equivalent of 6 or 12 paying patients. Mobile CT scanners are available and are mounted in tractor-trailers. These units hold promise for fieldwork, but the remains or artifact still need to be moved into the scanning gantry. There are also portable CT scanners available, but even these units are extremely heavy and the subjects still need to be moved into the scanner. Anytime the subject is moved, there are the risks of damaging the remains or moving whatever is inside those remains around, altering the internal context. Even if the subject is already out of context, for example, at a museum, it would still need to be moved into the scanner. If mummified human remains are to be placed in a scanner that is used for patients, care must be taken not only to protect the scanner environment from the mummy but also protect the mummy from contaminants in the imaging center environment. A method that has served to stabilize the mummy for transport and protect the environment was first demonstrated to us by Gino Fornaciari, a paleopathologist, during a field project in Popoli, Italy. The study necessitated transporting a mummy from a crypt to the imaging facility. The mummy was first protected by wrapping it in acid-free paper and then sealed in a continuous sheet of clear plastic film (Figure 3.42). This procedure stabilized the mummy for transport and protected the CT scanner environment and the mummy. The remains never had to be unwrapped at the scanner site as CT technology images are captured through most existing materials. Another major disadvantage associated with CT scanning is the misapplication of settings. After careful transport of the subject to the scanner, suboptimal data collection can result from individuals operating the CT unit who are inexperienced in examining mummified remains. As demonstrated by our experience with the mummy from the Barnum Museum, the technologist may need to spend hours using trial and error to locate the correct algorithm that will result in the most useful diagnostic images. CT scanners have been designed for use on living people and have preset protocols, or algorithms, “built in” for data manipulation. These protocols, designed for hydrated tissue, were intended to increase the patient throughput and, ultimately, the productivity of the imaging facility. A bone algorithm increases edge enhancement, while soft tissue algorithms decrease edge enhancement and apply edge smoothing. Unfortunately, these protocols do not always select the best algorithms for dehydrated or mummified remains. Also, the specific protocols vary among the many manufacturers of CT equipment. A

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Figure 3.42  Mummy wrapped in acid-free paper, then “sealed” with a continuous plastic wrap, cushioned, and gently strapped for travel by ambulance. The plastic wrap decreases the potential for contamination of the CT imaging equipment as well as the mummy.

skilled paleoimager must apply the protocols creatively to acquire optimal images from mummified remains. In a field situation, a systems specialist from the manufacturer may be sent along to operate the instrumentation. These individuals may have little experience with the CT scanning of living humans and no experience with CT imaging of mummified human remains. Proper data collection requires the skills of a specially trained paleoimager knowledgeable about various imaging modalities, manipulation strategies for data collection for anthropological and archaeological research, mummification methods, and burial practices. Unfortunately, radiologists do not generally possess these skills.

Direct Digital and Computed Radiography The technology that led to the development of detectors for CT found another application. If film could be replaced in conventional radiography, it would eliminate a number of problems. The same type of postprocessing procedures applied in CT imaging could be employed to eliminate repeat films. Once film was no longer used as the image receptor, wet processing would be a thing of the past. Imaging departments would no longer need to pay for maintenance of automatic processing units. It would no longer be necessary to

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recover silver from used fixer. In fact, with the processor gone, the space it occupied could certainly find a more profitable use. Two approaches were employed to solve the problem. The first, more commonly referred to today as direct digital radiography or DR, was created employing an early, second-generation CT unit design. General Electric Medical Systems termed the unit Scan Projection Radiography (SPR), and used a high collimated fan beam x-ray source that moved in conjunction with a linear detector array moving across the patient (Bushong 2008). The principal disadvantage of SPR was the several seconds required for the “translate” motion across the patient to acquire the image. The long acquisition time frequently failed to eliminate patient motion. To eliminate the problem, another approach was developed. The fan beam was replaced by an area beam that would cover a 14 × 17 in. (35 × 43 cm) area, and the linear detector array was substituted by one of two technical approaches to image acquisition. The first, known as a charge-coupled device or CCD, was composed of either amorphous silicon or a selenium-based material and directly generated electrical impulses proportional to the x-rays incident on the detector. Many CCDs are electrically linked together to form a matrix. The second approach, promoted by Canon, employs “complementary metal oxide semiconductor” (CMOS) microprocessors that convert light to an electrical signal. A matrix of CMOS devices requires less power consumption than the CCD approach. Both CCD and CMOS systems are directly linked to a computer that processes the data and within several seconds of the exposure, the image appears on the monitor. The other approach taken by Kodak, Konica, and Fuji is known as computed radiography or CR, and employs a photostimulable phosphor plate. However, instead of being directly connected to the computer that will process the data, the plate is placed into what appears to be a regular cassette. Following exposure to radiation, the cassette containing the plate is put into a “CR reader.” In the reader, a laser scans the surface of the plate, releasing the x-ray energy captured by converting it to flashes of light. The flashes are converted to an electrical signal that is then processed by the computer within the reader to produce the image that appears on the monitor. Of course, there is debate over which system is better. Each has its advantages, but the principal gain of the DR system is speed. Since it eliminated the middle step, the reader, it can produce an image in a couple of seconds where the CR system may requires a few minutes. If we are working with patients and concerned about throughput, time is a real consideration. When dealing with mummified or skeletal remains, the difference of a minute or so is not very significant. Therefore, the discussion of advantages and disadvantages will basically disregard the time factor. Instead the focus will be on portability, suitability in a wide range of applications, image quality, and cost. Since the CR plate is loaded into a “plate holder” or cassette, it can be taken wherever there is an x-ray source. The CR reader can be located thousands of miles away. This was demonstrated during a study of the “Amazonian Princess,” a fake mummy, at a Las Vegas, Nevada museum owned by the magician David Copperfield. A more complete description of the Princess is given in Chapter 9. The Fuji NDT research and development facility in Stamford, Connecticut, provided five plates for the study. To minimize risk of the plates being exposed during airline security screening procedures during transportation, they were shipped directly to the museum. Since the CR reader was back in Connecticut and we didn’t know if the plates had been exposed to radiation during a preflight inspection, the plates were exposed to fluorescent light for 30 min to “clear” them. The study was conducted with both Fuji CR plates and Polaroid film. The latter was employed to ensure that acceptable

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Figure 3.43A  An AP projection with the Fuji CR system of a portion of the right side of the chest and arm of the Amazonian Princess. Note the cow ribs (A), the tacks (B) holding the arm together, the wires (C) forming the fingers, and the material (D) covering the arm and hand.

images would be obtained prior to leaving the museum. Following the study, the plates were shipped back to Stamford and placed into the reader. Even though approximately a week had elapsed between the time the plates were exposed and processed, there appeared to be no loss of image quality with the time delay (Figures 3.43A and 3.43B). DR can also be portable. The Canon CMOS system can be coupled with a portable radiographic unit, in the United States with a MinXray® and in Great Britain with Xograph Healthcare, Ltd. The 17 × 17 in. (43.2 × 43.2 cm), the flat plate is connected to the computer by a cord that can be up to 21 ft (7 m) in length. Although we have not had the opportunity to test the system on mummified remains, we were able to use a Canon system on a cadaver at University College Dublin at Dublin, Ireland, in July 2008 (Figure 3.44). The system performed outstandingly. It was particularly advantageous to see the images within seconds of the exposure. Which system, CR or DR, would be more suitable in a variety of situations? There were two limitations noted with the DR approach. Although most imaging studies will have a source-to-image receptor distance (SID) less than 21 ft (7 m), the maximum cord length could present a problem. In the study of plaster casts in the Slater Museum, discussed more thoroughly in Chapter 9, a 50 ft (15.25 m) SID was necessary. Although wireless DR systems are now entering the market, a long SID would require multiple exposures to produce sufficient radiation to expose the plate without overheating the unit. With any DR system, multiple exposures are not possible. As soon as an exposure is terminated, the computer begins processing the image. Probably all major medical centers and most hospitals have moved or are in the process of moving away from film to a filmless approach with either DR or CR. Manufacturers

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Figure 3.43B  A composite created with five Polaroid images covering the same region as seen in the Fuji CR image. The ribs, tacks, and wires seen in the Fuji image were also clearly visible in the Polaroid image. However, since Fuji CR had a greater latitude than the Polaroid film, the material covering the arm and hand was seen clearly only on the former.

A

B C

A

Figure 3.44  An image of a cadaver taken with a portable Canon DR system. The oblong shapes (A) were created by the handholds in the board beneath the cadaver. Also seen on the image are a calcified femoral artery (B) and a fracture of the distal femur (C).

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have applied the same philosophy in developing the equipment so little thought has to go into the imaging process. Units now have preprogrammed algorithms that are designed for living patients and render images with a balance of contrast and density. The optimal medical CR image has a sensitivity, or S value, of approximately 200. For an AP projection of George/Fred’s chest at 70 kVp and 1.6 mAs, the S value was 243. Within a wide range of kVp (Figures 3.45A and 3.45B) and mAs (Figures 3.46A and 3.46B) values, the algorithm will automatically adjust the appearance of the image. Unlike film radiography, kV doesn’t control contrast with a CR system. Remember the concept of a characteristic curve discussed in Chapter 2? It is a graphical representation of the intensity of radiation exposure and the resulting density on the film (see Chapter 2, Figure 2.3). The acceptable exposure was in the narrow region of the straight-line portion of the graph. The slope of that segment identified as the latitude or gradient determined the image contrast. The graphical representation for a CR system is quite different (Figure 3.47). There is no toe or shoulder. Also note that the slope, termed gradient, or G value, in Konica systems and latitude, or L value, in Fuji, is maintained across the entire graph. For the Konica system employed to produce the images in Figures 3.45 and 3.46, the algorithm maintained the G value at about 2.35. Therefore, CR systems developed for the living are less than satisfactory for imaging the remains of the dead. However, the same technology has been modified for industrial applications. The industrial systems are less concerned with radiation dose to the object under examination than their medical counterparts. If small parts are the focus of the study, CR plates with smaller pixels requiring higher radiation doses are necessary.

Figure 3.45A  The AP chest was taken at 100 kVp at 6.4 mAs. That is approximately 40 kVp higher than the optimal kV used with conventional radiographic or Polaroid film. The S value dropped to 17; however, the algorithm adjusted the appearance of the image to maintain a G value of 2.35.

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A

Figure 3.45B  In this example, the kV was reduced to 40, but the mAs remained constant at

6.4. The poor visualization of the spine and liver (A) suggested an underpenetrated image. The S value shot up to 1764, but the algorithm was able to maintain the G value of 2.35. However, the high S value indicated that insufficient radiation had reached the plate; this appearance is termed quantum mottle.

Figure 3.46A  For this image, 70 kV was used at 100 mAs. The mAs was 60 times the optimal value and resulted in an S value of 4. Once again the algorithm was able to compensate and produced a G value of 2.39.

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Figure 3.46B  Once again the kV was set at 70, but the mAs was reduced to 0.8. Although the mAs was very low, the resulting S value was 489. Although there was a tremendous difference in mAs, because the G value was maintained at 2.35, the two images seem identical in appearance.

Similar to their medical counterparts, manufacturers have developed specific algorithms for each type of material that might be radiographed. Robert Lombardo (Lombardo 2008), an applications specialist from FUJIFILM NDT Systems, explained the principal differences between medical and industrial CR. Because of the tremendous

Density

CR

Film

Exposure

Figure 3.47  The graphical representation between the intensity of radiation exposure and the resulting density for film and CR system.

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range of materials that might be examined in industry, algorithms have been designed for penetration settings from 50 to 350 kV. Since an x-ray tube is incapable of producing the high kV required for more dense materials, such as thick steel found in ships and submarines, a radioactive source, such as iridium or even cobalt, is necessary to provide the required penetration. In addition, to ensure that sufficient x-ray photons reach the CR plate, the exposure times may range from 20 s to 1 h or more when a radioactive source is employed to image very dense material. Because of the wide range of material densities, the Fuji industrial CR readers are calibrated for five times the radiation dose (10 mR) of their medical counterparts (2 mR). For the Fuji system, it was discovered that the rubber algorithm produced the greatest detail of mummified remains (Figures 3.48A and 3.48B). As previously mentioned, the CR system has the capability of correcting for small errors in the technical factors that were set for a particular exposure. If too much radiation was used, an overexposure, the unit can more easily make corrections. However, if the plate was underexposed, the system would be unable to render an acceptable image. On a conventional radiograph, the underexposed film would appear “light,” but on the underexposed CR image it has more of a “salt and pepper” or speckled appearance. This appearance is termed quantum mottle and is due to insufficient radiation reaching the plate (see Figure 3.45B). Thus far, all the modalities discussed utilized radiation to produce images. In the mid1980s, another modality was introduced that didn’t employ an x-ray source, but rather used a high-intensity magnetic field. Initially termed nuclear magnetic resonance (NMR) the name was changed to magnetic resonance imaging (MRI) because of the bad connotations associated with the word “nuclear.”

Figure 3.48A  A lateral skull of George/Fred taken on a Konica medical CR system.

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Figure 3.48B  George/Fred’s lateral skull taken on a Fuji industrial CR system and processed with a rubber algorithm.

Magnetic Resonance Imaging (MRI) Unlike radiography, which is based on the differential absorption of the radiation transmitted through a patient, MRI or simply MR detects the quantity and distribution of mobile hydrogen protons within the patient. Although hydrogen is found in a number of compounds within the body, in many instances it is locked into a crystalline structure and is not mobile. However, the hydrogen within the water molecule is quite mobile and is the primary source of the MR image. A more complete description of the physical basis for the modality can be found in Westbrook and Kaut (1999). For the purpose of this text, a more generalized, less technical overview will be presented. Hydrogen is an unusual atom. In its most abundant form, it has a nucleus containing only a single positively charged proton. Only in its isotopic forms are one or two neutrally charged neutrons included in the nucleus. In a magnetic field, the proton will spin on its axis, or precess. The rate of precession is proportional to the intensity of the magnetic field. Before we go further into the imaging process, a review of the basic laws of magnetism is necessary. All magnets have north and south poles. There are lines of force that run from north to south outside the magnet and south to north inside the magnet. Poles with like charges or lines of force repel, whereas unlike poles or lines of force attract. The attraction or repulsion between two magnets is directly proportional to the intensity of the magnetic field and inversely proportional to the square of the distance between them; this is also known as the inverse square law as it applies to magnetism.

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Materials can be classified according to their reaction to magnets. Ferromagnetic material, such as iron, is strongly attracted to magnets. Diamagnetic materials, such as gold and aluminum, are weakly repelled. Paramagnetic material, such as gadolinium, is weakly attracted. Nonmagnetic materials, such as glass, ceramic, and wood, are not affected at all by magnets. The magnetic field that we experience when walking about on the Earth is relatively low and equivalent to about 0.5 gauss (G). A “gauss” is an older and less frequently used unit of magnetic field measurement in medical imaging. It is strong enough that a ferromagnetic compass needle can indicate the direction of the magnetic north pole; however, it is not of sufficient strength for imaging purposes. The unit of magnetism used for imaging purposes is the tesla (T), named after Nicoli Tesla, who did extensive research with electricity and magnetic fields. One tesla equals 10,000 G. For high-field MRI, the magnetic field strength is 1.5 to 3 T, or roughly 30,000 to 60,000 times stronger than the Earth’s geomagnetic field. Now back to the H1 protons. Normally, these protons are randomly aligned throughout the body (Figure 3.49A). When a strong external magnetic field is applied (B0), the protons are forced into alignment with the overwhelmingly more powerful external field. They tend to align either parallel (low energy) or antiparallel (higher energy) to the field (Figure 3.49B). Parallel and antiparallel pairs cancel each other out. Since nature favors a lower-energy state, there will be a greater number of parallel protons. This imbalance leaves a remainder of protons available for imaging (Figure 3.49C), and aligned with B0, but out of phase (Figure 3.50). In a 1.5 T magnetic field, approximately 7 out of every 1 × 105 hydrogen protons will remain. That may not seem like many, but since humans are made up of 70%–80% water and there are 1 × 1023 hydrogen atoms per cubic centimeter, there are literally millions of individual hydrogen protons available for imaging, though the overall number is dependent on the tissue type and the strength of the magnetic field. When radiofrequency (RF) energy is transmitted into the sample, several things will happen. First, all the remaining protons will be gathered together from their naturally outof-phase precessions and be placed in step with each other. Once organized in this fashion,

Figure 3.49A  Randomly aligned hydrogen protons within the body.

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B0

Anti-parallel

Parallel

Figure 3.49B  When a strong external magnetic field (B0) is applied, the protons tend to align antiparallel or parallel.

B0

Protons available for imaging

Figure 3.49C  After the antiparallels cancel out the parallels, the remaining protons are available for imaging.

B0

Figure 3.50  The parallel protons will align with B0, but will be out of phase.

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Radiofrequency

Figure 3.51A  The protons will all be in phase, forming a net magnetic vector (NMV).

they are aggregately termed the net magnetic vector (NMV) (Figure 3.51A). Then, the NMV will be pushed from a low-energy parallel alignment to a higher-energy transverse alignment (Figure 3.51B). They will remain in this state as long as external RF energy is applied. Once the external RF energy is terminated, the NMV will begin to lose the absorbed energy (Figure  3.52) and simultaneously go through two separate processes. First, the NMV will begin to relax from the excited state to the preferred longitudinal state. As it does so, it gives up its accumulated energy to the surrounding tissue lattice. This process is called T1 recovery or spin lattice. T1 time is defined as the time is taken to recover 63% of the longitudinal magnetization (Figure 3.53). The second process that affects the NMV involves the individual protons within its bulk. Once the external RF energy is terminated, the individual protons begin to dephase and lose step with one another. This process is driven by the interaction and exchange of energy between the individual protons and is called T2 decay. T2 decay is defined as the time taken for 37% of the transverse magnetization to be lost (Figure 3.54). The rate at which both these processes occur is influenced by the strength of the magnetic field and the biological state of the imaged tissue. The latter plays a critical role when imaging preserved, dried, and/or decaying tissues. During the T1 and T2 processes, the NMV, an aggregate of multiple small magnetic fields, is precessing on its axis. This magnetic field, though small, is precessing at 8–127 MHz B0

Radiofrequency

NMV

Figure 3.51B  The radiofrequency will be absorbed, and in doing so the NMV will be pushed into the higher-energy transverse alignment.

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Paleoimaging: Field Applications for Cultural Remains and Artifacts B0

NMV

Figure 3.52  Once the RF is terminated, the protons begin to lose the absorbed energy and return to B0, the longitudinal magnetization.

Longitudinal Magnetization

depending on field strength, 0.2–3.0 T accordingly. According to Faraday’s laws of induction, a magnetic field of changing intensity perpendicular to a wire will induce a voltage along the length of that wire. MRI exploits the fact by placing a special wire conductor, called a coil, perpendicular to the precessing NMV. There are coils of many shapes and sizes, and it is best to choose the smallest coil possible for the body part to be imaged. Since the amount of voltage induced depends on both the strength and rate of change of the magnetic field, we can see that even a weak magnetic field is capable of inducing a measurable current when precessing between 8 and 127 million times per second. The induced current, similar to the NMV itself, is not a single entity but composed of the sum of its parts and is of the same frequency as the precession of the NMV. Careful analysis of the signal will yield valuable information about the protons that created it. As discussed earlier, the rate at which T1 and T2 occur is dependent on the nature of the tissues. By manipulating the excitation and relaxation process, we can, in essence, interrogate the protons and extract valuable information regarding the quantity and binding characteristics of water molecules.

63%

Time

Figure 3.53  The T1 time signifies the loss of energy to the surrounding tissue. The process is defined as the amount of time taken to recover 63% of the longitudinal magnetization.

Transverse Magnetization

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37%

Time

Figure 3.54  T2 decay is defined as the time taken for 37% of the transverse magnetization to

be lost.

The information gained through this manipulation, though valuable, is limited to two dimensions: frequency and amplitude. To create an image, we need to add information regarding the precise location of each component of the signal within the sample. This is done through a process called spatial localization. Although a detailed understanding of spatial localization is not necessary for this text, the basic concept should be mentioned. The entire basis of clinical MRI is that protons will precess in a magnetic field. The rate of precession is extremely precise, and for hydrogen it is equal to 42.57 MHz per tesla. We can vary the rate of precession by varying the magnetic field, and by doing so we can vary the frequency of the signal induced in the coil. If in addition to the main magnetic field, we apply changeable magnetic fields in the X, Y, and Z planes, then we have the ability to alter the precession in any direction we choose. These additional components are called gradient coils and are really nothing more than electromagnets arranged around the bore (tunnel) of the main magnet. Though very complex in application, the concept is simple. Apply a changing electromagnetic field by altering power to the gradient in any one direction, and you will alter the precession of the individual protons along that axis. Record the values, and repeat the process in another plane. By repeating this process thousands of times per second, we can not only determine the T1 and T2 properties of the imaged tissues but also their precise anatomical location within the sample. The T1 and T2 properties are important because they tell us the type of tissue and its general state of health. The location is important because it allows us to image not in a single slice, like early CT scanners, but rather across a large volume of tissue that the computer can segment into slices for easy viewing. The added benefit of MRI is that since the image is created not by the attenuation of an x-ray beam but rather by the concentration and distribution of water molecules, the image is extremely sensitive to subtle tissue changes that would otherwise be lost to other modalities. The disadvantage of this increased sensitivity is that it comes with a much more complex series of user-defined parameters for obtaining images. Whereas x-ray is limited to a few basics and CT a few more, MRI has dozens of user-selectable parameters that create hundreds of thousands of possible combinations. With MRI in widespread clinical use since the mid- to late 1980s, the parameters are well understood for clinical human imaging. In the end, we are really trying to obtain an image that is optimized for either the T1 properties of a tissue, the T2 properties of the tissue, or the overall density of protons contained in the tissue. We do this by manipulating the parameters within long-established guidelines.

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Paleoimaging: Field Applications for Cultural Remains and Artifacts Table 3.1 Signal Characteristics of Tissues with Spin Echo T1 and T2 Imaging Hyperintense on T1

Hyperintense on T2

Fat Subacute blood Melanin Myelin Highly proteinaceous fluids Cholesterol Gadolinium enhancement

Water CSF Subacute hematoma Inflammation Highly proteinaceous fluids Most lesions

The basic schematic diagram of how the excitation and relaxation processes are controlled along with the functions of the gradients is called a pulse sequence. Though complex in application, the pulse sequence is nothing more than a preset series of events that the computer uses to produce an image. The pulse sequence has several components that are controllable by the operator, and a few of these basic parameters are applicable here. The few parameters we will mention in this text will be those with the greatest impact on the images we wish to obtain. TE (echo time) is defined as the time between the RF excitation pulse and the time we sample the resultant signal. The longer the TE, the less the signal available, because of the rapid rate of the T1 and T1 processes. TR (repetition time) is defined as the time from one excitation pulse to the next, or how long we wait before repeating the entire process. By altering these values, we can formulate an image with the tissue characteristics we desire to see (Table 3.1). These two parameters have a great impact on the signal characteristics of the resultant image. For example, fat will be bright and water will be dark. The other parameters we set have little impact on the signal characteristics, but they play a critical role in the overall quality of the image. When discussing image quality, we are discussing a trade-off between image resolution, or detail, and signal-to-noise ratio (SNR). An image can have a very high resolution but a low SNR. Such an image will be of little value because although we have great detail, there is not enough signal to see it. The opposite is also true. A high-SNR image with low resolution, though pretty, will not provide sufficient detail to visualize the intended structures. The key parameters needed to balance SNR and resolution are field of view (FOV), slick thickness, and image matrix. In short, the more protons included in each portion of the image, the greater the SNR. Thick slices and large FOVs accomplish this nicely. Image resolution is more a factor of the displayed image. The more tiny pieces an image is divided into (pixels), the better the detail. But if the pieces are too small or if the images were collected with a small FOV and thin slices, there may not be enough signal to fill the pixels and the resultant image will be very noisy. Images can be classified as T1 or T2 weighted depending on which process contributed more to the final image. With a T1-weighted image, fat has a higher signal than water (Figure 3.55). High signal appears white on the displayed image, lower signals are generated as shades of gray, and no signal, such as received from air or cortical bone, is black. T1 images provide excellent anatomical detail. On the other hand, a T2-weighted image provide a higher signal from water and a lower signal from fat (Figure 3.56). T2 images are advantageous for demonstrating pathological processes,

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B

A

Figure 3.55  A T1-weighted image at the level of the cerebellum (A). Note the high signal from the retro-orbital fat.

such as edema, that have high “water” content. However, T2 images don’t provide as much anatomical detail as T1-weighted images. Through careful manipulation of the technical parameters, a skilled operator can create images to enhance or feature almost any disease process. Because MR primarily provides information on the location of mobile hydrogen within a body, it would seem of little value in the examination of mummified remains. Notman et al. (1986) published a report following the examination of a mummy with MR looking for residual moisture. They stated, “… It appears MRI is unsuitable for the paleopathologic investigation of dehydrated structures.” At the time they were correct, as early attempts to utilize MRI to image mummies and mummy tissues realized little success. Three notable exceptions are a modern mummy created in the ancient Egyptian method in 1994 at the University of Maryland by Bob Brier and Ronn Wade (Quigley 1998), a dog mummified to document and analyze the desiccation process by Notman and Aufderheide (1995), and brain tissue removed from the preserved skull of an Indian Bog Mummy and embedded in agar (Notman 1983). Since that time, we have, on several occasions, been successful in incorporating MRI into the imaging workup protocol for the evaluation of mummified remains. With mummified tissues, it is sometimes necessary to override the standard prescan process and tune the system manually. It is also helpful in some cases to add an isolated source of mobile protons to “load” the coil. This can be accomplished by placing saline IV bags or water bottles in the coil with the body part to be imaged. The mobile protons in the water trick the system into “thinking” that the tissue within the coil is hydrated. Once the system tunes in appropriately, the operator can fine-tune the scanner and obtain satisfactory images even with the bags removed.

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A

B

Figure 3.56  A T2-weighted image at approximately the same level as in Figure 3.55. In this

case, the high signal is from the aqueous fluid in the eye (A) and the cerebrospinal fluid (B) anterior and lateral to the pons.

Case Examples of MR Application to Mummified Remains Sabia A Peruvian mummy known as Sabia had been recovered from the ancient ceremonial center at Pachacamac (Figure 3.57). The mummy was scheduled for whole-body evaluation with CT. Since the resources were available MRI was performed. Our initial thoughts were

Figure 3.57  The Peruvian mummy known as Sabia.

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that given the anhydrous nature of the mummy, MRI would yield little or no information. Our hope was that if the mummy was preserved with resins or oils, there may be minute quantities of trapped moisture that could possibly yield an MR signal. Though initially unsuccessful due to the failure of the automated signal detection and processing built into the system, further attempts with manual tuning were more successful. It should be noted that all commercial MRI scanners have automatic prescan “tuning” software packages. These programs are designed to find the biggest signal peaks and, based on resonant frequency, identify fat and water. The signal was then optimized, and the scan was allowed to proceed. MRI of the brain was the first exam performed on Sabia. Axial (Figure 3.58A) and sagittal (Figure 3.58B) slices were obtained through the brain from the vertex to the skull base. For correlation, approximate slice positions were compared with corresponding CT slices and reformatted CT images (Figures 3.59A and 3.59B). The same procedure was followed for the chest, abdomen, and pelvic regions. It should be noted that the increased sensitivity of MRI, one of its greatest benefits, may also be responsible for its failure in some cases. The sensitivity of MRI is measured on the order of parts per million (ppm). This means that MRI can detect anatomical and pathological changes in tissues before they present clinically in many cases. In its application to the field of mummy research, it means that contaminants in the imaged sample can have a devastating negative impact on the final image. The big concern here was the presence of anything metallic within the remains. Metallic contaminants can be from many sources including soil, rock, pieces of broken tools, religious and funerary artifacts, and miscellaneous offerings as seen in the mummy James Penn (Figure 3.60). The magnitude and

Figure 3.58A  An axial MR image through the brain of Sabia.

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Figure 3.58B  A sagittal MR image through the brain of Sabia.

Figure 3.59A  The axial CT image that corresponded to the same level as the MR image of Sabia. The CT images were required to confirm the structures seen in the MR images.

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Figure 3.59B  A reformatted 3D CT image demonstrating the structures visualized on the sagittal MR images.

Figure 3.60  Coins (arrows) located within the oropharynx and esophagus of James Penn.

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Figure 3.61  The mummified remains of James Penn.

type of contaminants in any mummy depends on many factors. The age of the mummy, methods of preparation and preservation, materials used, and methods of storage all play a significant role. In general, the more contaminants, the lower the probability that MRI will be successful. Additionally, no mummy should be taken into MRI until first evaluated and cleared with either diagnostic radiography, CT, or both. James Penn The second mummy evaluated was from Reading, Pennsylvania, and identified as James Penn (Figure  3.61). The individual was purportedly embalmed with formaldehyde in 1895, making him one of the earlier cases of formaldehyde embalming in the United States. The mummy was imaged on a 1.5 T Achieva Scanner (Philips Medical Systems) using the Sense body coil and 16-channel head coil. As with the previous specimen, the scanner was unable to tune in on the signal automatically. Manual tuning on this system was also ineffective, so it was necessary to load the coil by placing several IV bags containing normal saline around the head and body of the mummy (Figure 3.62). The addition of the saline provided the mobile protons necessary to tune the scanner, and once tuned the scans were completed without further problems. T1 images were obtained in 7-mm-thick sections from multiple planes in the head, body, and extremities. Although

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Figure 3.62  Saline bags placed around the head of James Penn within the head coil of the MR

unit.

thick sections would not provide detailed images, it would indicate the location of residual fat. James Penn was remarkably well preserved, and his internal organs were intact per CT scanning. Sylvester The third mummy, identified as Sylvester, was embalmed with arsenic in the late 1800s and is on exhibit at Ye Olde Curiosity Shop in Seattle, Washington. His mummified remains weighed approximately 80 lb (36.4 kg), which was extremely unusual. Since a body is composed of 70%–80% water, after undergoing dehydration, the weight should be about 20%–30% the premortem weight. One possible explanation is that embalming fixes the proteins and dehydrates the tissues to reduce the effects of decomposition. However, body fat is not affected by the embalming fluid and does not provide fuel for decomposition. Over time, solid fats will liquefy. An inspection of the mummy revealed a “sheen” on the surface of the remains, and it appeared to be moist (Figure 3.63). Analysis of the skin confirmed high levels of arsenic and also lipids. Since on a T1-weighted image fat provides a high signal, MRI could be utilized to further verify the theory that lipids were migrating to the surface. The remains were imaged on a 1.5 T Avanto scanner (Siemens Medical Systems). The entire body was scanned with small FOVs and matched coils. Sylvester, similar to James Penn, was extremely well preserved. All internal organs had been identified during a previous CT examination and the facial features well retained. The embalming process was so effective that the details of the eye were clearly visible (Figure 3.64). Since the mummy had been embalmed with arsenic, the MRI was more complicated than expected. The heavy metal properties of arsenic made it very difficult to tune in on the resonant frequency. Once tuned, however, the images were satisfactory. Regions of high signal, white areas on the T1-weighted MR images, were noted in a number of internal and external locations on the multiplanar images (Figures 3.65 and 3.66).

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Figure 3.63  The mummified remains of Sylvester. With the exception of the skull, there

appeared to be a “sheen” over the body. In this photograph, it can be seen in the reflection of light from the arm (arrows).

The images appeared to reveal the locations of lipids that had not been affected by the preservation process and probably liquefied. Although the contribution of arsenic cannot be determined at this time, it appeared that the high signal was solely due to the lipids. The margins of the tissues were not sharply defined, because thick slices were necessary to provide enough tissue to get a sufficient signal. To demonstrate anatomical clarity, CT images from the same level were examined. In all three mummies, MRI was able to generate useful images. Although not acceptable by current clinical standards, the images added valuable information about the condition of the mummies. We were able to determine the presence, structure, and nature of

Figure 3.64  A close-up photograph of Sylvester’s eye.

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D

B

E C

C

A

Figure 3.65  An axial MR image at the level of the heart. A high signal was noted not only on the surface structures, such as the back (A), abdomen (B), axillae (C), and left hand and arm (D), but also internally on the wall of the right ventricle of the heart (E).

C D B

A

C

E

F

Figure 3.66  A sagittal MR image close to the midline of the body demonstrated a correspond-

ing high signal from the surface of the back (A), abdomen (B), and the anterior aspect of both arms (C). Internally, once again high signal was noted in the wall of the right ventricle; it was also seen in the region of the annulus fibrosus of the intervertebral disc (E) surrounding an area of low to no signal from what appears to be the nucleus pulposus (F).

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many tissues and organs within the body. MRI was also more successful than CT in finding regions of fat deposition and retained moisture and, though not the gold standard, we believe MRI should be included as part of the comprehensive diagnostic evaluation of all mummified remains.

References Aufderheide, A. C. 2003. The Scientiἀc Study of Mummies. Cambridge U.K.: Cambridge University Press. Beckett, R., J. Posh, C. Czaplinski, G. Conlogue, L. Quarino, J. Kishbaugh, and A. Bonner. 2008. Moving toward field application of percutaneous needle biopsy in mummified remains using a non-gravity-dependent needle scrape/aspiration technique with CT and endoscopic guidance—A preliminary study. Paper presented at the 35th Annual Meeting of the Paleopathology Association, April 8–9, Columbus, OH. Bushong, S. C. 2004. Radiologic Science for Technologists. 8th edition. 422–440. St Louis, MO: Elsevier Mosby. Bushong, S. C. 2008. Radiologic Science for Technologist. 9th edition. 428. St Louis, MO: Elsevier Mosby. Cockburn, A., E. Cockburn, and T. Reyman, Ed. 1998. Mummies, Disease and Ancient Cultures, 2nd edition. Cambridge, U.K: Cambridge University Press. Conlogue, G., J. Jones, R. Beckett, M. Biesinger, L. Engel, and M. Smith. 2005. Imaging the legend of Marie O’Day. Paper presented at the 32nd Annual North American Paleopathology Association Meeting, April, Milwaukee, WI. Cox, J. E., C. Chiles, C. M. McManus, S. L. Aquino, and R. H. Choplin. 1999. Transthoracic needle aspiration biopsy: Variables that affect risk of pneumothorax. Radiology, Vol. 212: 165–168. Eiseberg, R. L. 1992. Radiology An Illustrated History. 430. St. Louis, MO: Mosby-Year Book, Inc. Fauber, T. L. 2009. Exposure variability and image quality in computed radiography. Radiologic Technology, Vol. 80(3): 209–215. Hiss, S. S. 1983. Understanding Radiography, 2nd ed. 302. Springfield, IL: Charles C., Thomas. Larscheid, R. C., P. E. Thorpe, and W. J. Scott. 1998. Percutaneous transthoracic needle aspiration biopsy: A comprehensive review of its current role in the diagnosis and treatment of lung tumors. Chest, Vol. 114: 704–709. Lombardo, R. 2008. Personal communication. Notman N. H., J. Tashjian, A. C. Aufderheide, O. W. Cass, O. C. Shane III, T. H. Berquist, and E. Gedgaudas. 1986. Modern imaging and endoscopic biopsy techniques in Egyptian mummies. American Journal of Roentgenoogyl, Vol. 146: 93–96. Notman, D. N. H. and A. C. Aufderheide. 1995. Experimental mummification and computed imaging. In Proceedings of the First World Congress on Mummy Studies, February, 1992, Vol. 2: 821–828. Santa Cruz, Tenerife, Canary Islands: Archeological and Ethnographical Museum of Tenerife. Notman, D. N. H. 1983. Use of nuclear magnetic resonance imaging of archeological specimens. Paleopathology Newsletter, Vol. 43: 9–12. Quigley, C. 1998. Modern Mummies. 115–119. Jefferson, NC: MacFarland & Company, Inc. Ruhli, F. J., H. Jurg, and T. Boni. 2002. CT guided biopsy: A new diagnostic method for paleopathological research, Technical note. American Journal of Physical Anthropology, Vol. 117(3): 272–275. Seeram, E. 1985a. X-Ray Imaging Equipment, 162. Springfield, IL: Charles C Thomas. Seeram, E. 1985b. X-Ray Imaging Equipment, 164. Springfield, IL: Charles C Thomas. Seeram, E. 2001. Computed Tomography Physical Principles, Clinical Applications and Quality Control. 3. Philadelphia, PA: WB Saunders Company. Webster, J. G. ed. 1988. Encyclopedia of Medical Devices and Instrumentation. 834. New York: Wiley. Westbrook, C. and C. Kaut. 1999. MRI in Practice, 2nd edition. 1–17. London: Blackwell Science. Wolbarst, A. B. 1993. Physics of Radiology. 321. Norwalk, CT: Appleton & Lange.

Endoscopy Field and Laboratory Application of Videoendoscopy in Anthropological and Archaeological Research

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Ronald Beckett and Gerald Conlogue Contents Introduction Evolution of Endoscopy in Anthropology Instrumentation Medical versus Industrial Endoscopes Anatomy of a VE The Insertion Tube The Physics of Fiber Optics The Distal Tip The Proximal End Light Source Camera Control Unit/Monitoring/Data Recording and Storage Quick Look Systems Biopsy and Retrieval Tools Instrumentation Summary Endoscopic Laboratory and Field Applications Supporting Imaging Techniques Conventional Radiography Direct and Computed Radiography Fluoroscopy Computed Tomography (CT Scan) Complementary Nature among Methods Technological Disadvantages of Videoendoscopy Anthropological Applications of Videoendoscopy Burial Practices Mummification Methods Age at Time of Death Dentition Paleopathologies

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Biomechanical Stress Mechanism of Death Sampling Artifact Retrieval Soft and Bony Tissue Biopsy: Histology and Pathology Chemical Composition Ancient DNA Radiocarbon Dating Archaeological Applications of Videoendoscopy Preexcavation Tomb Evaluation Remote Imaging and Tomb Sampling Conservation Preparation Artifact Analysis Emerging Applications: Endoscopic-Guided Light Reflectance/Absorption Analysis Experiment 1: Subject #1, Preserved Feline Experiment 2: Subject #2, North American Mummy (circa 1900) Experiment 3: Subject #3, Pa-Ib (2000–1500 BC) New Kingdom Period Egyptian Mummy Experiment 4: Comparisons between Experimental Subjects Potential Future Applications of Videoendoscopy: Transluminescence for Relative Density among Structures Alternate Light Endoscopy Endoscopy Summary and Future Applications References

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Introduction Anthropological and archaeological research often relies on direct observational analysis of objects of antiquity and anthropological remains. Although the information derived from visual inspection can be great, limitations to this approach do exist. What is seen on the surface or through natural openings cannot assist in gathering data about what lies beneath. If a researcher does want to see beyond the surface, destructive methods such as autopsies are often used to see “within” the human remains or object. Videoendoscopy is a tool that can gather imaging data from within research subjects by using nondestructive or minimally destructive approaches, thus making it a valuable tool in these target research domains. Videoendoscopic techniques have been employed to gather data from mummified human remains, skeletal remains, archaeological objects such as ceramics, and archaeological sites prior to excavation for a number of years. Endoscopy has also been used in anthropology and archaeology for observational data collection and target biopsy. Recently, an increased variety of applications for videoendoscopic technology have been realized. Videoendoscopy has been utilized for anthropological data collection to assist in the determination of age at the time of death, biomechanical stress, paleopathological conditions, burial practices, mummification technique, dentition analysis, soft tissue or bony biopsy for histological and pathological determinations, biopsy or material collection for

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chemical analysis or radiocarbon dating, as well as artifact analysis of objects wrapped within mummy bundles. Videoendoscopy has been used in extreme field settings and in preexcavation tomb evaluation. Newer application possibilities for endoscopy include alternate light visualization, endocranial mapping, and transluminescence for relative density estimations. The major advantages of the videoendoscope (VE) lie in its flexibility of application and its portability. When used in conjunction with varied imaging technologies, the VE has been able to assist in the collection of otherwise unavailable data. Further, the VE often helps alleviate the need to autopsy mummified human remains, which helps preserve the remains for future research and maintain appropriate respect for the deceased while increasing our understanding of the journey of human life on earth.

Evolution of Endoscopy in Anthropology Not long after the inception of the flexible fiber-optic endoscope in the early 1970s and its subsequent use in medicine, the technology was applied to mummified remains. The early reports, starting in about 1978, applied the technology following the medical model. The endoscope was used to biopsy target tissue from within a body cavity of mummified remains (Tapp et al. 1984). Later reports demonstrate the adoption of the bioarchaeological model in that the technology has increasingly been applied in field research (Beckett and Conlogue 1998). It is from this broader application that endoscopic technologies are reaching their fullest potential in anthropological research. Arthur Aufderheide, in his book The Scientiἀc Study of Mummies, provides a synopsis of the literature related to endoscopic applications in mummy science. These reports include the intent of each study, including the following: thoracic biopsy, coprolite retrieval, biopsy studies, methodology, body cavity examination, organ identification, coffin contents, and methods (Aufderheide 2003). More recently, endoscopy has been included in multimodality nondestructive methodologies as demonstrated in a recent study from Korea in which researchers differentiated among organs within a child mummy (Kim et al. 2006). Various applications of endoscopic methods in field anthropological research settings have been conducted and reported at a variety of professional meetings (Beckett and Conlogue 1998; Conlogue et al. 1999; Beckett et al. 1999a, Beckett et al. 1999b; Posh and Beckett 2000; Duclos et al. 2000; Beckett and Guillen 2000; Conlogue et al. 2003; Bravo et al. 2003a; Beckett et al. 2003; Cartmell et al. 2003; Bravo et al. 2003b; Ventura et al. 2004; Conlogue et al. 2004; Beckett et al. 2006; Conlogue et al. 2005; Conlogue et al. 2008a), demonstrating its wider application in nonmedical environments including remote research facilities, within tombs and crypts, and other field settings. When endoscopy was first employed in the study of mummified remains, the work was conducted at medical facilities, requiring the remains be brought to the hospital, where a target was determined by analysis of imaging data, and a biopsy was conducted or an artifact was retrieved. The major drawback of this model is that the remains require transportation, risking not only damage to the remains but also shifting of contents within the remains or within the wrappings, thus altering the internal context or spatial relationships within those remains. This shifting could in turn lead to misinterpretation of collected data.

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More recently, videoendoscopy has been employed in the field in remote research locations, adopting the anthropological and archaeological model for collection of data. Data can be collected on site, at the point of excavation, which helps maintain the original context. Data collected in this fashion maintains the original position and spatial relationship of the information, decreasing the potential for misinterpretation. The techniques of videoendoscopy, when appropriately applied, are minimally invasive, and typically do not require openings to be made into the remains as such openings usually already exist. Using the anthropological and archaeological model, large sample sizes can be researched, improving the interpretability and statistical power of the collected data. It is the intent of this chapter to provide the reader with application guidelines regarding the use of videoendoscopy in anthropological and archaeological research. This chapter includes the technical aspects of videoendoscopy, situational variables regarding its application, supporting technologies that enhance the utility and value of the data, data collection methods for observational studies as well as tissue collection procedures, and the data obtainable via videoendoscopy. Research examples are utilized where appropriate within the chapter. Instrumentation Endoscopy can be described as looking inside an object, person, or an animal with a tool designed to provide visualization of an internal target object or body cavity. Endoscopy is also utilized to explore enclosed spaces hidden from direct visualization. Although we usually relate the use of an endoscope to the medical profession, endoscopy has been widely applied to the industrial arena as well. Early endoscopes were essentially straight tubes of varied lengths and diameters (Figure 4.1). A light source was secured to the insertion end, and visualization was accomplished by looking through the tube. In the early 1970s, fiberoptic technology had advanced to the point where fiber-optic bundles could be tightly bound in an insertion tube encased in flexible material. This gave the endoscope flexibility

Figure 4.1  Author using a straight endoscope to examine the internal features of a plastinated heart at the University of Maryland School of Medicine. Note the endoscopic image of the chordae tendineae seen on the monitor.

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A

B

Figure 4.2  Flexible fiber-optic endoscopes. Shown here are an industrial videoscope (A) and a standard medical bronchoscope (B).

while still providing a lighted viewing area and enhanced visualization through a lens located at the distal tip of the instrument (Figure 4.2). Maneuverability is provided by finewire remote control of the tip of the scope, giving the operator the ability to navigate the endoscope within body cavities or organs. Medical endoscopes were, and continue to be, developed and configured for diameter and length related to the medical need and target organ anatomy. Industrial endoscopes were developed related to their specific application requirements as well. In order to provide documentation of the endoscopic field of view, a 35 mm still camera was attached to the eyepiece of the endoscope and internal parts of a human or an object could then be photographed (Figure 4.3). Soon, small video cameras attached to the eyepiece of the endoscope were added, enhancing the way endoscopic data could be collected. It was not until the 1990s that true videoendoscopes (VEs), or videoscopes, were developed. A VE is different from standard endoscopes in that the video camera itself has been miniaturized and positioned at the distal end or tip of the flexible instrument (Figure 4.4). This allowed for greater video resolution, and the data collected therefore had greater interpretability. Current VEs can now collect and record images in high-definition formats using compact flash cards or digital video cassettes. Endoscopes can use various light sources, including “cold” light sources, which can be quite compact, making the instrument extremely portable. The only other necessary instrumentation required for the VE is a camera control unit, which controls the exposure conditions of the video signal. The camera control unit is also compact and easily portable. Medical versus Industrial Endoscopes Medical endoscopes are developed and configured related to the medical need and target organ. Longer scopes can be used to traverse the gastrointestinal tract, whereas shorter scopes would be used to examine the posterior oral pharynx. Diameters also vary according to purpose (Figure 4.5). Medical endoscopes can be either flexible or rigid. Flexible scopes are required for such target organs as the lungs or the colon, whereas

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Figure 4.3  Image capture system using a 35 mm camera adapted to the objective lens of a medical endoscope.

Figure 4.4  The distal tip of an industrial videoscope showing the housing and lens for the miniaturized video camera.

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Figure 4.5  Examples of endoscope diameter variations. From left to right: 10 mm medical colonoscope, 6 mm industrial video scope, 6.5 mm medical bronchoscope, and a 4.5 mm pediatric medical endoscope. Note the lack of a biopsy channel on the industrial videoscope.

rigid scopes are commonly used for arthroscopy techniques as well as transthoracic, transabdominal, and transpelvic endoscopy. Medical applications of endoscopy include those with both diagnostic and therapeutic goals. Medical diagnostic uses include direct visualization of tissues or membranes, secretion aspiration for microbiological analysis, and tissue or lesion biopsy. Medical therapeutic uses include lesion excision using lasers, organ reexpansion, and secretion aspiration for luminal passageway patency. When used in anthropology and archaeology, endoscopy is employed primarily as a diagnostic tool providing direct visualization for data analysis and documentation, and for tissue biopsy. Industrial endoscopes have also developed to match their intended application. They can also be either flexible or rigid. Flexible scopes are used in situations where the structure has numerous curves or turns to be negotiated, such as the internal works of a jet engine. Rigid industrial scopes, often called borescopes, are used when the path to the target object is straight ahead. Industrial endoscopes are also used in police work, giving officers the ability to “see” into a room or around corners. Endoscopes have been used for continuous surveillance and in forensic settings to look into closed compartments for evidence or contraband. Medical and industrial endoscopes are different in design due to their specific applications. The internal fiber-optic bundle, lenses, and optics are essentially the same on both medical and industrial scopes. However, the insertion tubes of medical scopes are covered with a flexible sheath, which allows for smoother passage and easier decontamination between patients. In contrast, the insertion tubes of industrial scopes are typically housed in a stainless steel mesh, giving them greater durability (see Figure 4.2). When selecting an endoscope for use in the field or remote areas, the added durability of the industrial scope is a positive feature. The supporting equipment used in medical endoscopy, such as light sources, camera control units, visualization, and recording equipment, can be bulky as it is designed for use within a medical facility. It is often mounted on a cart, which can be moved about the medical facility, or permanently mounted in an endoscopy suite. In contrast, industrial endoscopic supporting equipment is designed to be portable and is therefore smaller, lighter, more durable, and can be battery operated for remote applications (Figures 4.6A and 4.6B). Both medical and industrial endoscopes are available in a variety of diameters and can be as small as 1.9 mm (Figure 4.7). There are fiber-optic systems used in medical settings

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(A)

(B) Figure 4.6  (A) Portable industrial endoscope system showing a light source, camera control unit, and the videoscope. Also pictured is a goggle-style visual monitoring device. (B) Portable videoendoscopy setup in research setting at Cornell University. System show includes a printer (far left) and an 8 mm video camera for visual monitoring and data recording.

that are small enough to travel inside a blood vessel. Medical and industrial endoscopes also vary in length. A 60 ft (18.29 m) industrial endoscope is available and has applications in archaeology for preexcavation tomb analysis. Endoscope characteristics such as length, diameter, maneuverability, lens (near focus, far focus, right angle, stereo lens for measurements, etc.), light source, data collection, portability, and durability all provide

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Figure 4.7  A 1.9-mm-diameter industrial endoscope with video camera adapted to the objective viewing lens. Light source is a handheld LED system, enhancing the instrument’s portability and applicability in remote regions where only tiny openings exist.

the researcher with an instrument capable of being matched to specific research objectives (see Figures 4.2 and 4.7). In order to fully understand the application of the endoscope in anthropological and archaeological research, it is important to understand its functional components. We will describe the VE, as it is this type of endoscope that holds the most potential for directed research. This potential is due to the VE’s image-capturing capability, portability, and flexibility of application. The videoendoscopic system comprises the scope itself, a light source for illumination, a camera control unit, a system for recording data, a system for visualization, varied lens options, and biopsy or retrieval tools. Anatomy of a VE A VE can best be understood as a system having three structural and functional components. The three components include the insertion tube, the tip at the distal end of the insertion tube, and the control head at the proximal end of the endoscope (Figure 4.8). The Insertion Tube The insertion tube refers to the main body of the endoscope. In the case of the VE, the insertion tube is a flexible tube available in various lengths and diameters. Within the insertion tube is a series of continuous flexible glass fibers that serve to deliver light from an external light source. In conventional endoscopes, additional glass fibers also return the image to an ocular lens at the proximal end. In contrast, the VE has a miniature video camera at its distal tip, eliminating the need for the image return fibers.

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Figure 4.8  Gross anatomy of a videoscope: A is the distal tip that houses the camera and lens, B is the insertion tube housing the fiber-optic light guides, and C is the proximal end that houses the various controls.

The Physics of Fiber Optics At this point, it is important to understand what fiber optics are and how they transmit light and images. Individual optical fibers are made of pure glass and can be as thin as a human hair. The diameter of the glass fibers is what gives them their ability to flex and bend. These individual optical fibers are bundled into what are called optic cables and can be of varied lengths. The bundles are used to transmit light signals over long distances. These fiber-optic bundles make up the bulk of the insertion tube of a VE. Figure 4.9 depicts the structure of a single optical fiber. At the center of each fiber is the core, which is the thin pure glass through which the light travels. The next layer is the cladding, which is the outer reflective optical material surrounding the core. The reflective material reflects light back into the core. Finally, there is a buffer coating that serves to protect the cladding and the core from damage and moisture (Freudenrich 2001). The bundles can be made up of hundreds or thousands of individual optical fibers. The bundles are protected by the insertion tubes’ outer “jacket.” In the case of medical endoscopes, these jackets are made from a tissue-neutral material, whereas industrial endoscope jackets are typically made from a fine stainless steel mesh, making them durable and rugged. There are two types of optical fibers, including single-mode fibers and multimode fibers. Single-mode fibers have small-diameter cores of about 9 μm and transmit infrared laser light (1300–1500 nm). In contrast, multimode fibers have larger core diameters of

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Glass core

A single optic fiber

Buffer coating

Figure 4.9  Structure of a single optical fiber.

about 62.5 μm. These fibers transmit infrared light (850–1300 nm) from light-emitting diodes (Freudenrich 2001). Additionally, there are optical fibers that are made from plastic, typically having a large core diameter (1 mm), and transmit visible red light (650 nm). In order to understand how an optical fiber works, consider the behavior of light. Light travels in a straight line. If you shine a flashlight straight into a cave, the light travels straight ahead. If the cave bends or twists, in order to illuminate that part of the cave with your flashlight, you may place a mirror at a specific angle, thus reflecting the light around that bend. If there are multiple bends, you could place many mirrors along the caves’ contours and “bend” the light side to side along the cave walls. Optical fibers work in much the same way. Essentially, the light in an optical fiber travels through the glass core. When the light meets a bend, it is reflected back into the core by constantly bouncing from the cladding or mirror-lined walls surrounding the core (Freudenrich 2001; see also Figure 4.10). This principle is called total internal reflection. Different substances have different indices of refraction, that is, the manner in which the direction of light is altered. In the physics of refraction, the amount of light refracted is dependent upon the difference between the indices of refraction of the materials and what Endoscopic light source

Cladding (Mirror-lined walls, moves light as inner surface bends)

Light signals Emitted light from distal end of scope illuminating the field of view

Figure 4.10  Diagram showing how light traveling through the fiber core is reflected back into the core when a curve is encountered in the light path.

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Paleoimaging: Field Applications for Cultural Remains and Artifacts Critical Angle Internal Reflection Cladding on the inner surface

Long axis

Glass core

Critical angle

Normal axis

Figure 4.11  Diagram of the critical angle associated with fiber optics.

is called the critical angle (Freudenrich 2001). In physics, the critical angle is that which is perpendicular to the surface. However, in fiber optics, the critical angle is described with respect to the parallel axis running down the middle of the core. Thus, the fiber-optic critical angle is 90° minus the physics critical angle (Figure 4.11). In an optical fiber, the light travels through the core (high index of refraction) by constantly reflecting from the cladding (lower index of refraction) because the angle of the light is always greater than the critical angle. Light reflects from the cladding no matter what the angle of the fiber itself is, even if it runs in a full circle. The cladding does not absorb any light from the core; therefore, the light wave can travel a considerable distance. Some of the light signal does degrade within the fiber. This is mostly due to impurities in the glass. The extent that the signal degrades depends on the purity of the glass and the wavelength of the transmitted light. For example, at 850 nm, there is a 60 to 75%/km degradation. At 1300 nm, there is a 50 to 60%/km and, at 1550 nm, there is a greater than 50%/km degradation. The higher the wavelength, the less the degradation of the light signal. Some premium optical fibers with an extremely pure glass core show much less signal degradation and can be less than 10%/km at 1550 nm (Freudenrich 2001). The Distal Tip The distal tip of the VE houses the video capture component and, like a video camera, can be fitted with various lenses including close-up lenses (near focus), distant view lenses (far focus), wide angle lenses, right angle lenses, and split screen stereo, or binocular lenses for 3D and measurement applications (Figure 4.12; see also Figure 4.4). The distal tip is typically maneuverable from controls found at the proximal end. The lens selection characteristic allows the researcher to match the lens, and therefore the image and data collected, to the research objectives and to adapt to imaging challenges within any given subject or object of study. For example, Figure 4.13 shows two views of the same thoracic area, one using a near-focus forward view lens and the other using a far-focus forward view lens. The far-focus lens gives a better view of the entire internal thoracic cavity. The distal tip of the endoscope houses the terminal end of the fiber-optic bundles used to deliver light. If the far-focus lens is used to examine a large open space, such as in preexcavation tomb analysis, additional illumination may be required.

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Figure 4.12  Various interchangeable lens used in videoendoscopy. From left: Forward view near focus, right angle view near focus, and stereo lens used for measurements and 3D renderings.

The Proximal End The proximal end of the VE has various components and is the command center of the scope. Directional controls, which are manual or electronic depending on the scope type, can manipulate the direction of the tip of the VE in four directions while it is within an object. The tip of some scopes can be manipulated greater than 90° in any direction. This allows the operator to seek out targets without having to have a direct path. Coupled with the lens options at the tip, the VE becomes an extremely flexible imaging tool. The proximal end also houses the command controls for the functions of the camera control unit (CCU). Depending on the options available on the CCU, the proximal tip can command such functions as freeze frame, digital zoom, image capture and storage, brightness control, white balance, and field of view manipulation (Figure 4.14). If equipped, the proximal end command center can also control digital measurement applications. This allows for measurement of objects within the subject of analysis. Light Source In order to see within closed objects devoid of ambient light, light is provided to the VE by a cold (low-heat-producing) light source. A fiber-optic light guide connects the light source with the VE. Light can then travel through the fiber optics of the VE insertion tube and illuminate the field of view at the distal tip. Light sources vary in their configuration and should be matched to the application at hand (Figure 4.15). For example, in field applications, compactness, portability, and battery operational capabilities are the major considerations. Light sources are available that weigh approximately

Figure 4.13  (See color insert following page 12.) A comparison of two views of the same internal

thorax. On the left is a video-endoscopic image of thoracic contents using a forward view nearfocus lens, while on the right the same thorax is imaged using a forward view far-focus lens.

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Figure 4.14  Proximal end of videoendoscope showing the tip directional controls at the top

with locking mechanisms and the imaging controls, including freeze frame, brightness, digital zoom, and store to disc controls. Additional settings are adjustable in the menu function.

4 lb, about the size of a hair dryer, and can be operated by battery. Other portable light sources are handheld, like a flashlight. These basic light sources are simple in their operational aspects as well with an on/off control and a brightness control. The light is typically derived from a halogen bulb. Portable light sources may also use LED lights for illumination. If the endoscopic application is to be conducted in a laboratory setting, additional light source options become available. Higher-wattage light is available as well as additional controls such as filters, exposure indexing, and air pumps. Camera Control Unit/Monitoring/Data Recording and Storage The camera control unit (CCU) receives and processes the image from the camera at the distal tip of the VE. The controls on the CCU are similar to those found on the proximal end of the VE, with additional exposure settings such as automatic gain control, which amplifies a dark image. The CCU prepares the image for export to a monitoring system

Figure 4.15  Various light sources used with portable endoscopy. The two light sources on the left are battery operated, increasing portability.

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Figure 4.16  Top left—Camera control unit that processes the image for export. Center left—

Back section of the camera control unit showing various image output ports. Bottom left— Hi8mm video camera used for visual monitoring and image recording. Top center—Mini DV recording deck with monitor (also capable of compact flash card image storage). Bottom center—Mini DV camera used to monitor and record images. Top right—Standard monitor. Bottom right—“Heads up” goggle-style monitor for use in tight places. Note the Hi8mm and MiniDV cameras have the added advantage of imaging through the lens.

and the various image-storing devices. The image outputs available are standard video signals such as s-video and BNC outputs. This allows the CCU to send the image to a video monitor for operator observation during the procedure. Digital output allows the image to be sent to a digital recording device such as an optical disk or computer. If a mini digital video camera, equipped with an s-video line-in port and a monitoring screen, is used, it may function as both a monitor and an image storage device. Mini digital video cameras have great field applicability as they are compact and have the further advantage of being able to capture through-the-lens images of the research site, subject, and other project variables. Also available for image monitoring and image capture are miniDV recording decks and DVD recorders. The miniDV recording deck is similar to the miniDV camera but does not have through-the-lens capability since it does not have a lens for input. Figure  4.16 shows a portable CCU as well as a variety of monitors and recording devices. DVD recorders are limited in that additional monitoring must be considered. More recently, systems that can capture and store data on compact flash cards of varying memory capacities have been used. Also, resolution of the recorded and stored data has been improved by using HD imaging and recording systems. These systems are straightforward in their operational characteristics and provide added increased flexibility and quality to data collected from VE instrumentation.

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Figure 4.17  Battery-powered “quick look” systems using LED light sources. Images can be recorded directly to compact flash card or exported via standard video output signals to additional monitoring and image recording systems.

Quick Look Systems Another group of endoscopes are the ultraportable systems. These endoscopes are compact, lightweight (weighing under a pound), and battery capable, enhancing portability. We have found these systems very useful in two applications, including when a quick look is needed and when the research setting is extremely remote. As a quick look system, we have used the ultraportable system to move quickly between a large group of mummies, looking for comparisons or for collecting specific data points such as the internal structures of various skulls. The size of these quick look systems, the ease of operation, and their “low-tech” application make them ideal for use in extremely remote settings where instrumentation size and dependability are critical. Typically, these quick look systems include an insertion tube of varied lengths. One system includes various-length insertion tubes that interface with a common command unit, increasing their flexibility of application (Figure 4.17). Most of the quick look systems come with a lens that has a 3 to 6 in. (7.62 to 15.25 cm) focal length and is a forward view format. A right-angle mirror adaptor is usually provided for 90° viewing. The light source of these quick look systems is typically a set of LEDs at the distal end that is battery powered. The light does not travel through optical fibers. With many of the quick look endoscopes, the direction of the distal end cannot be changed and is a major drawback of these systems. The command unit receives the image from the distal lens and is processed.

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Figure 4.18  External biopsy channel attached to videoendoscope. Standard medical biopsy forceps shown here enter the field of view for documentation of the biopsy procedure.

Because the image travels back to the command unit from the lens at the distal end of the scope, some resolution is lost. The battery-powered command unit may also have an onboard color monitor, a/v output ports, digital zoom capabilities, and video or still shot capture to a compact flash or SD card. Balancing the limitations of the quick look systems against their advantages, we find that they do have a place in bioarchaeological research when used in appropriate settings. Another great advantage is that these quick look systems are a fraction of the cost of the more sophisticated VE systems, making them obtainable with even the most modest research budgets. Biopsy and Retrieval Tools Once a target within an object has been visualized and recorded, the research goals may call for biopsy of ancient tissue or artifact retrieval. Various tools are available for these procedures. Tissue biopsy can be carried out much as it is in living subjects, and a wide variety of tools are available. Fine needle biopsy is the method of choice in that it leaves the target organ well intact. However, the yield from fine needle biopsy is often too small for analysis. Ancient tissue is dry and brittle, and these conventional biopsy methods often produce a low yield. Alternate tools with larger retrieval capacity are often necessary. Long, narrow tweezers or varied forceps can be employed. Some industrial VEs do not have a biopsy channel, as do their medical counterparts. To remedy this, two methods are available. The first is to affix a biopsy channel to the external surface of the VE (Figure 4.18). This, of course, increases the diameter of the system and may decrease flexibility regarding insertion routes. The second approach is similar to the laparoscopic medical approach in that visualization is provided from one point of entry, while the biopsy tool is introduced into the field of view from another point of entry (Figure 4.19). We have been successful in extracting a large renal stone using this method from an 18th century mummy discovered in a crypt beneath the Church of the Holy Trinity in Popoli, Italy. Artifact retrieval can be accomplished using these same procedures.

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Paleoimaging: Field Applications for Cultural Remains and Artifacts Laparoscopic Biopsy Approach Multiple points of entry

Endoscope system for illumination and visualization

Biopsy/retrieval tool

Body surface

Emitted illumination

Target within body

Figure 4.19  Diagram of laparoscopic biopsy approach.

Instrumentation Summary A major advantage of the VE in archaeological and anthropological applications is its portability. Its size makes it easy to transport, and the ease of data acquisition and battery operational characteristics make the VE a meaningful field paleoimaging data collection tool. The major limitation of the VE systems is not being able to find an entry point in the mummy or artifact. The diameter of the VE may limit its insertion. The smallest VE has a diameter of 4 to 5 mm. Smaller-diameter endoscopes are available, but the video capture system is not at the distal end. Therefore, there is a loss in resolution as the image is transmitted through lengths of optical fibers. Care must be taken not to damage the mummy or artifact. This usually requires considerable practice of insertion and removal techniques with the instrumentation. Care must also be taken not to cross-contaminate human remains or to contaminate any sample collected. Endoscopic Laboratory and Field Applications The power of the VE in archaeological and anthropological applications is truly realized in the field. However, some cases require more powerful complementary imaging tools that cannot be transported to the site because of their size, necessitating VE application in the laboratory or imaging center. Additionally, any new field application and training on the field use of VE should be initially conducted under laboratory conditions. As each supporting imaging technique is discussed, notation is made regarding it being a field or laboratory application. As a discussion of data that can be collected is presented, the need for laboratory practice will become apparent. The portability of the VE makes it a useful tool for data collection in remote and tight spaces. Videoendoscopy has been applied in varied environments such as jungles, under water, within tombs and crypts, and in open extreme environments such as deserts or wet rain forests. Regardless of VE application in the field or in the laboratory, knowing where you are and where you are going within an object is paramount. Knowledge of anatomical landmarks, appearances of desiccated tissues, and practice all aid in knowing what is seen and what data need to be collected. Without this experience and knowledge,

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the data collected via videoendoscopy may not only be confusing but can also lead to gross misinterpretations. Individuals who wish to include videoendoscopy in their paleoimaging data collection instrumentation should first apprentice with a seasoned endoscopist and bioarchaeologist. Supporting Imaging Techniques Videoendoscopy is best used in combination with other imaging modalities. Research variables such as limited work space within a tomb or crypt may dictate using the VE as the primary paleoimaging instrument and following those data with focused alternate imaging as dictated by the findings. Other situations allow for alternate paleoimaging applied prior to VE application. Regardless, each of the paleoimaging techniques is complementary and adds power to the data collected regarding its interpretability. Conventional radiography and computerized imaging systems are discussed in greater detail in Chapters 2 and 3 with only brief descriptions included here in the context of their association with videoendoscopy imaging. Conventional Radiography Conventional radiography is typically conducted in laboratory settings due to the necessity of a dark room and chemicals for image development. However, since portable x-ray tubes and their control panels are available and can be made ready for travel, techniques have been developed to construct dark rooms in the field for film processing and x-ray cassette loading. These field dark rooms require creativity and will increase the total travel container count and often exceed weight allowances. A standard radiograph produces a 2D image in varied shades of gray, some not within the range of vision of the human eye. The image, given appropriate exposure, positioning, and developing parameters, will yield a high-resolution shadowgram of the object. Spatial relationships are not apparent using a single view; therefore, at least two views are usually taken. Still, the absence of color, contour, and depth may limit the interpretability of the data. Once the image is reviewed, further data analysis targets can be determined. The VE can then approach these targets demonstrating color, contour, and depth, and, if desired, retrieval. Instant radiography is conducted in the same manner as standard radiography, except that no dark room is required. The image is presented on instant film, which develops in 1 min and is portable. Instant film is preferred in the field as dark rooms and developing chemicals can be avoided, increasing the portability of the radiography applications. The images produced are of very high quality. One variation is that the image is reversed, in that what would be light on a standard x-ray film is dark on the instant film. If desired, the image may be scanned and digitally reversed to mimic the standard x-ray image. Photographic paper too can be used for x-ray imaging. Details regarding the use of photographic film can be found in Chapter 2 of this text. Videoendoscopy combined with conventional radiography, using instant film or photographic paper image receptors, creates a nearly ideal combination of technologies that can be applied in the field. Both conventional and instant radiography has been used in conjunction with videoendoscopy to locate targets within the mummified remains, to document the position of the endoscope, and to document any alterations following the endoscopy procedure such as artifact retrieval maneuvers.

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Direct and Computed Radiography Direct radiography is a method by which the radiographic image is captured on a special receptor and fed directly into a digital processing system or computer (see Chapter 3). Computed radiography (CR) is accomplished by using a special reusable image receptor that is fed into a special reader. The advantage of direct and computed radiography is that the process is filmless, there is no trash as is the case with instant film or need for developing chemicals needed for standard radiographic film, and the image can be instantly manipulated within certain limitations to bring out the varied shades of gray. The systems do require a computer, and in the case of CR, a reader, thereby limiting some field applications unless the computer is capable of rugged travel conditions. Currently available reader systems for CR that yield high resolution are large in size. However, as technology continues to develop, videoendoscopy imaging associated with computed or direct radiography will make a meaningful field paleoimaging combination. Although the special image receptor cassettes can be taken into the field and later returned to the processor, the lag in development time negates its use in conjunction with videoendoscopy for the purpose of endoscope location. Fluoroscopy Fluoroscopy is “real-time” x-ray that can be seen on a monitor. Fluoroscopy is used in clinical medicine to guide such procedures as cardiac catheterization, and pulmonary biopsy procedures. Individual images can be collected at any time either on standard x-ray film, instant x-ray film, or digitally. These images can document the site of an anomaly or the location of a biopsy or artifact prior to retrieval. The advantage of fluoroscopy as related to videoendoscopy is that fluoroscopy can allow the operator to guide the VE with much greater assurance of direction and location within the mummified remains. We have used fluoroscopy in conjunction with endoscopy to assist in the retrieval of 21 coins from the posterior oral pharynx and proximal aspect of the esophagus of a late 19th century mummy housed at the Auman Funeral Home in Reading, Pennsylvania. Since there were so many coins, fluoroscopy provided real-time images of the coin locations (Conlogue et al. 2008a). During this procedure, we employed standard postural drainage and percussion techniques commonly used in clinical medicine to mobilize pulmonary secretions. Using alternate posturing of the mummy required repeated assessment of the coin positions in order to locate them endoscopically. In another case, we needed to directly visualize via endoscopy, the fracture characteristics of a skull fracture on the inner table of an Incan mummified head. We used fluoroscopy to successfully direct the VE to the exact location of the fracture within the cranial vault (Figure  4.20). In this case, the internal characteristics of the fracture and the swollen appearance of the dura mater just below the fracture suggested that the fracture likely caused a hematoma in the region and may have contributed to the death of the individual. The VE image also demonstrated that the fractures occurred perimortem, as there was no evidence of bone healing along the fracture margins. The major disadvantage of fluoroscopy is that the instrumentation is bulky and not easily transported. Additionally, there is a much greater risk of x-ray exposure associated with continuous systems such as fluoroscopy. Generally, videoendoscopy in association with fluoroscopy is limited to laboratory research; however, industrial units are available that are portable and lightweight. The major drawback to the portable field units is that they have a small field of view.

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Figure 4.20  An example of fluoroscopy used to direct the endoscope to a specific target within the mummified remains, in this case, the internal characteristics of a skull fracture seen in several endoscopic images.

Computed Tomography (CT Scan) Each of the previously described imaging techniques collects 2D data, which can at times raise new questions about the dimensions of an object or anomaly and its precise location and relationship to other structures within the subject. CT scans, as described in Chapter 3, collect data digitally as an x-ray source circles the object. The images are produced and presented as slices, much like sliced bread, or in volumes. Each slice can be of varied thickness, depending on operator settings. Basically, the thinner the slice, the more precise the data. Each slice can then be examined for anomalies and an idea of its exact location and size can be obtained. The CT image has a much higher resolution than standard radiography, potentially yielding more information. The slices can be postprocessed and manipulated digitally by stacking the slices and creating a 3D image that can be further manipulated to show only specific densities like bone, effectively removing the skin and organs in order to study the skeletal system. The image can be remanipulated to study just the surface characteristics of the mummified remains. Image manipulation can “strip” away wrappings to “see” what lies beneath without needing to unwrap. Newer methods include manipulating the image to create a virtual “fly-through” of hollow structures within the subject. The virtual fly-through technique produces an image similar to videoendoscopy and can see into places that the VE cannot if there is no access route for the VE. In an attempt to develop a field procedure similar to the virtual fly-through in a laboratory setting, we compared the images obtained from the CT fly-through technique with standard endoscopic images. The VE was directed to collect images of specific structures within the cranial vault of a mummified Peruvian head. The CT virtual fly-through technique was also employed to

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Figure 4.21  Image comparisons between CT fly-through imaging (left panels) and the corresponding videoendoscopy images (right panels).

create images of those same endocranial structures. We found that the images were comparable, with the endoscopic images being less subject to digital drop-out as the CT system “smoothes” the data collected (Figure 4.21). Additionally, the endoscopic image demonstrated a truer color representation than did the CT system (Posh and Beckett 2000). Although CT is a powerful imaging tool, its major drawback is its size. Although there are “portable” units available, the instruments are not easily transported, often weighing 1000 lb (453.59 kg) or more. This necessitates bringing mummies or artifacts to the imaging center, whether that is in a medical facility or in the back of a tractor-trailer truck. This increases the risk of damage to the mummy or artifact that could potentially altering the spatial relationships among anatomical landmarks. Transporting the mummy to an imaging facility may also cause movement of artifacts within burial bundles, altering the internal context and decreasing the interpretability of the data collected by altering their original associations. An ideal complementary application using videoendoscopy with CT scanning is that of CT-guided biopsy or artifact retrieval procedures. The CT scan can help direct the endoscope to the precise location of the target structure, reducing the procedure time while increasing accuracy. Complementary Nature among Methods To compare the field applicability of each complementary paleoimaging method, a rating scale was used to assess the relative strengths and weaknesses of each modality across

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Table 4.1  Comparison of Complementary Methods Method Conventional radiography Photographic film radiography CR and DR Fluoroscopy Computed tomography Videoendoscopy

Image Quality (0–5)

2D

4 4 4 3 5 4

X X X X X X

3D

Portability (0–5)

Field Rating (0–10)

X X

5 5 3 0 0 5

9 9 7 3 5 9

several key variables valuable to field paleoimaging research. Although each of the imaging methods is applicable to anthropological and archaeological research, standard radiography using instant film as image receptors and videoendoscopy are best suited for field applications (Table  4.1). Fortunately, data collected from these methods do provide volumes of usable research information. Each research project will dictate the paleoimaging priorities and what data may be collected. Regardless of order of application, each method complements the other. A logical sequence of image collection would be to begin with conventional radiography following standardized procedures, interpret the data collected, and follow up with VE directed toward specific targets for identification or to add clarity to an identified anomaly seen on the radiograph. If further clarification or localization is required, the decision to transport the mummy or artifact to an imaging facility for CT scanning can be considered. Careful assessment of the possible gains versus the possible risks must be considered. Each paleoimaging method adds increasingly more detailed information to the case, complementing the previously obtained data. Technological Disadvantages of Videoendoscopy Perhaps the greatest disadvantage of endoscopic application in anthropological settings is the need for a route of entry into the object, mummy wrapping, or mummy body cavity. Additionally, once the endoscope is inside, there needs to be space to allow it to be maneuvered within the target cavity. Much of the data collected via endoscopy is visually descriptive, leaving room for inadvertent misinterpretation. Use of endoscopic instrumentation is an invasive procedure, which can carry the additional risk of contamination, particularly if tissue sampling is being conducted. If sampling is the objective of the particular procedural application, the procedure becomes destructive. In this case, careful protocols and documentation procedures, including route of entry, sample characteristics, and sample site, must be adhered to. Anthropological Applications of Videoendoscopy Videoendoscopy can aid the research team through image collection of varied anthropological, archaeological, and paleopathological data. These data, particularly when coupled with radiographic images, can help in the evaluation of burial practices, mummification techniques, age at the time of death, dentition, paleopathologies, and biomechanical stress. Additionally, videoendoscopy can be instrumental in collecting samples for further analysis, such as aDNA and radiocarbon dating. At times, data may be collected that suggest a mechanism of death.

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Using the light source as a steady and constant light output, the VE may assist in determining relative densities among various structures that had been exposed to the same taphonomic forces over time. Using alternate light through the VE may help differentiate among tissue types and margins as well as detect fungal invasions on mummified remains. Burial Practices The VE can be used to collect data regarding burial practices of a particular mummy or within a population of mummies. With visual data regarding burial goods, crosscultural comparisons can be made. Under direct visualization, internal aspects of mummy bundles can be examined. The use of body cavity packing, associated feathers for ornamentation or packing, additional bandaging, artifacts placed within the wrappings in the mummy bundles, or the mummies themselves of a given culture can all be determined. Sometimes, offerings were placed in the mouths of the mummies. These offerings can be documented employing videoendoscopy and used for comparisons to other mummies of that culture or an alternate culture. Often, what is buried with an individual tells us what was important to that culture and at times may indicate the status or occupation of the mummified individual. For example, a ceramic pot placed within the chest cavity filled with coca leaves coupled with the presence of coca leaves throughout the remains, including between the teeth, suggests that the coca held specific significance for those people, particularly if other mummies were buried in the same fashion. A mummy buried with weaving tools may suggest that the person in that mummy bundle may have been a weaver (Figure 4.22). An individual mummy buried

Figure 4.22  (See color insert following page 12.) Videoendoscopic images of various burial

practices seen from inside the wrappings. Shown here are weaving tools, feather, cotton, and wool packing, and a metallic object seen with twine passing through.

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with five shell necklaces, whereas other mummies in that population were only buried with one, suggests a higher social status for that individual. Obvious inclusion of shell or metallic artifacts may further indicate a unique social status. Artifacts found within mummy bundles may also suggest trade and commerce between different regions. The use of videoendoscopy for artifact analysis will be discussed in greater detail in chapters of Section III of this text. Mummification Methods A question that is important regarding mummified remains is that of determining through paleoimaging and other available evidence if artificial mummification was practiced versus natural mummification. The VE can collect data that may be useful in determining whether or not an individual mummy or a group of mummies were prepared for the afterlife or if the preserved body was a result of natural drying forces. One question that is not easily answered by conventional radiography is whether or not internal organs were removed. Naturally dried internal organs lose their density from dehydration and are not well demonstrated on x-ray. The VE can peer into body cavities and “see” organ remnants that were questionable or invisible on the radiograph (Figure 4.23). Additional body treatments can be seen using the VE, such as sutures and cut marks if the head was removed in order to remove the brain. Radiography may only show that the head is disarticulated but not necessarily indicate how it was disarticulated. Regarding Egyptian mummification practices, many times the cribriform portion of the ethmoid bone (Figure 4.24) has been manipulated or fractured to provide cranial access. Videoendoscopy can examine the details of this procedure, and the results can be compared to other imaging data (Figure 4.25) such as standard radiography and CT scans. In one such study (Nelson et al. 2007), we discovered unique cranial vault access variations among several Egyptian mummies using both endoscopic and CT images. Any packets holding the mummified organs that had been removed during the mummification process and then wrapped and placed back in the body of the mummy can be endoscopically visualized and imaged. External

Figure 4.23  Videoendoscopic image of internal organ remnants not seen on radiograph.

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Figure 4.24  Videoendoscopic images of intact crista galli and the cribriform plate. These

structures are usually destroyed during brain removal associated with some Egyptian mummification.

and internal body cavity surface features can be visualized endoscopically to determine if treatments with ointments or oils were used. Not only can the VE assist with determining whether or not artificial mummification was practiced, but a general assessment of the state of internal preservation can be made at the same time.

Figure 4.25  (See color insert following page 12.) Videoendoscopic images of the brain removal entry point in PaIb (left panels). Coronal section CT scan showing the opening into the cranial vault and a 3D reconstruction further demonstrating the entry point (right panels).

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Figure 4.26  Videoendoscopic images assisting in the age at death determination. Top left— Open fontanel. Top center—Auricular surface wear. Top right—Segmented sternum. Bottom left—Internal table cranial suture fusing. Bottom center—Palatine suture fusing. Bottom right—Symphysis pubis wear.

Age at Time of Death There are several markers that help determine age at the time of death. If the individual is less than 22 years of age, tooth eruption patterns and fusing patterns of long-bone epiphyses can readily estimate the age at the time of death. These features are demonstrated well with the radiograph. The VE can look at and document age at time of death criteria and add to the radiographic data. The teeth and their eruption pattern can be seen as well as the fusing pattern of the palatine sutures. Endocranial suture fusing patterns can also be visualized. Visualization of the segmented sternum can assist with aging the very young, whereas wear patterns on such structures as the auricular surface and the symphysis pubis can also be useful in estimating the age at time of death (Beckett et al. 1999a; Dulcos et al. 2000). Figure 4.26 presents several images of endoscopic views of anatomical features used as aging criteria. Dentition Dentition not only yields information about age at the time of death but can also give researchers clues regarding the dietary habits of an individual or populations of people. Wear patterns in younger individuals may suggest that sand inadvertently mixed in with the diet. High dental attrition at younger ages suggests a diet high in carbohydrates. Wellpreserved teeth with little wear and little attrition may suggest a higher-status individual. Complete dental surveys can be conducted using the VE. In the case of dental attrition, the VE can provide images of the mandibular and maxillary surfaces to document to what degree reabsorption has occurred, indicating when the tooth or teeth were lost. Additionally, horizontal growth arrest lines can be seen on permanent teeth, suggesting past systemic infectious processes. Abscesses with bone loss can be seen, suggesting that poor dental

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Figure 4.27  Videoendoscopic images of various dentition features.

conditions may have contributed to the death of that individual. Besides certain diseases, cultural habits such as tooth filing and decoration can leave their mark on the teeth as well. At times, specific tooth wear patterns may suggest an occupation held by the individual; for example, a v-groove among the molars suggests the repeated actions of a weaver who pulled yarn through the mouth to form a strand. Also, early dental practices such as tooth drilling can be seen, suggesting the level of sophistication of the medical practices of the population. Figure 4.27 presents several endoscopic views of varied dentition features. Paleopathologies Diseases can leave their traces on the bony structures or in organ remnants within mummified remains. Videoendoscopy can be used to directly visualize the impact of disease on the individual under investigation. Pulmonary diseases (Beckett et al. 2003) that can be seen in the remains include pulmonary adhesions (Figure 4.28), emphysema, and pulmonary fibrotic changes (Figure 4.29). Additionally, peritracheal lymphadenopathies (Beckett et al. 1999b) can be seen if they impose on the inner lumen of a preserved pulmonary airway (Figure 4.30). If an individual had meningitis, the meningeal grooves on the inner table of the cranium become deep, which can be seen via the VE (Figure 4.31). Additional endocranial lesions can also be visualized, such as those of the dorsal sella turcica, indicating a potential pituitary lesion. Calcifications seen on x-ray may be difficult to visualize with

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Figure 4.28  Videoendoscopic images of pulmonary adhesions. Image at bottom right is from a Chachapoya mummy from Leymebamba, Peru, whereas the other images are from a late 19th century historic mummy.

VE due to their position within the pulmonary matrix. However, on occasion, pulmonary lymph node lesions (Conlogue et al. 2008b) can be imaged endoscopically (Figure 4.32) and, if desired, extracted for paleopathological analysis. Renal stones have also been visualized and retrieved under VE guidance (Figure 4.33). Biomechanical Stress Bone responds to its environment and expresses wear and tear based on use and chronic inflammation. One particular biomechanical stress that can be directly assessed with the

Figure 4.29  Videoendoscopic images of pulmonary pathologies in a Chachapoya mummy in Leymebamba, Peru. The image on the left suggests pulmonary fibrotic changes, whereas the image on the right is of a lung suggesting emphysema. Note the large pockets, perhaps caused by loss of lung tissue seen in emphysema.

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Figure 4.30  Videoendoscopic images of the trachea of a mummy from Pachacamac. The image on the left shows proximal tracheal rings with distal tracheal narrowing. The narrowing is likely due to a peritracheal lymphadenopathy encroaching on the tracheal lumen. The image on the right is a closer view of the narrowing.

Figure 4.31  Videoendoscopic images of meningeal grooves on the inner table of the skull.

Figure 4.32  Radiograph showing videoendoscope position at the location of a pulmonary calcification. The resultant endoscopic image of the lesion (arrow) is shown on the right.

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Figure 4.33  Videoendoscope image of a renal stone (arrow) removal procedure using the laparoscopic method.

VE is arthritis. Arthritis of the spine (Figure  4.34), hip, shoulder, and knees can all be imaged and documented. Other biomechanical stresses that may be seen could be enlarged insertion points for skeletal muscles on the long bones indicating repetitive activity, such as rowing, in which the deltoid tuberosity would be enlarged. The significance of arthritis identification and its location is threefold. First, arthritis identification can help in determination of age at the time of death when used along with other indicators. Second, the location of the arthritis can help determine the type of repetitive work the individual may have been involved with. And third, little arthritis in an older individual may indicate higher status within a group or population. Old, bony fractures can also be assessed (Figure 4.35).

Figure 4.34  Videoendoscopic images showing vertebral abnormalities. Severe arthritic changes are seen on the left with vertebral fusing seen on the right.

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Figure 4.35  Healing rib fracture on a mummified canine (three views).

Mechanism of Death It is on rare occasions that the VE can assist in determining the mechanism of death. If there has been a traumatic injury to the skull, the angle of impact can be seen by bevel analysis from within the cranial vault. Skull fractures can be examined along the fracture line to determine if there has been any bony healing, which helps in determining if the fracture occurred near or around the time of death. Exit wounds from projectile injury can be assessed. On one occasion, a dart within the shoulder complex of a Chachapoya mummy in Leymebamba, Peru, perhaps with a poisoned tip, was located by x-ray and visualized by videoendoscopy (Figure 4.36). Often, the data collected are only suggestive and not definitive for mechanism of death; however, the data once collected and recorded can be assessed in combination with the results of other imaging modalities. Sampling Artifact Retrieval Artifact location is often accomplished with x-ray; however, artifact identification often requires the VE for accurate analysis. Once located and identified, it can be retrieved if the research goals call for it. Often, as a project begins, it is difficult to anticipate the location or presence of any artifacts. However, once they are exposed, decisions must be made to analyze and possibly conserve the object. If conservation is the goal, then retrieval should be attempted. Great care must be taken to extract the object with minimal damage to both the artifact and the mummified remains. Several retrieval tools work well for artifact removal, and each retrieval calls for creative application and tool selection. Section III of this text discusses endoscopy applications in artifact analysis and retrieval in greater detail.

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Figure 4.36  Videoendoscopic view of a dart within the tissue matrix of the shoulder region.

Soft and Bony Tissue Biopsy: Histology and Pathology One of the primary uses of the medical endoscope is to obtain samples for pathological analysis. These analyses can help determine tissue type and the presence of disease. It follows that the VE used for anthropological research can accomplish those same goals. In mummified human remains, tissue elements of organs and organ systems are not necessarily in their appropriate anatomical position, nor is their morphology the same as while living. In a crypt mummy from the Church of the Holy Trinity in Popoli, Italy, a biopsy was taken using the laparoscopic technique of what was believed to be lung tissue. After rehydration of that tissue, it was found to be diaphragm and not lung tissue. Even so, once the tissue was stained and examined microscopically, the sample demonstrated calcifications (Figure 4.37), indicating a long-standing disease process (Ventura 2002). Tissue sampling

Figure 4.37  Rehydrated and stained diaphragm tissue showing calcifications. Tissue samples were collected under videoendoscopic visualization.

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Figure 4.38  Various instruments used for tissue biopsy. Top left—Medical biopsy forceps and

cytology brush. Top right—Percutaneous needle. Bottom left—Miscellaneous medical instruments. Bottom right—Mechanics gripping device for larger samples.

can be used to determine if the tissue remnants are, in fact organs, thereby suggesting a mummification method that did or did not remove internal organs. Further, lymph tissue, calcifications seen on x-ray, and bony lesions can be biopsied and further analyzed for traces of disease. Following rehydration, the ancient tissue can be pathologically examined and probability data may be statistically determined if the population size is large enough. Biopsy can be conducted in a variety of ways. Biopsy using CT guidance (Chapter 3), the locator grid field technique (Chapter 2), and the laparoscopic biopsy technique described earlier in this chapter all demonstrate proven methods for target-specific biopsy. Standard medical biopsy forceps work well, but the yield is often too small for diagnosis. Larger collection tools and needle biopsy instruments can be used to enhance the yield and the diagnostic capability (Figure 4.38). Samples should be handled with the same care as if from a living individual. Contamination should be avoided, and sterile containers should be used. Chemical Composition Surface samples of textiles, ceramics, and skin can all be collected for chemical analysis. These analyses can help determine if an individual was treated with any substances that could have contributed to the mummification process. One such substance is arsenic. Arsenic was first used in the United States as an embalming agent late in the Civil War to preserve Union soldiers for funerals in the distant north (Aufderheide 2003). Following the Civil War, another not so noble use of arsenic preservation was employed. Unclaimed

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bodies of individuals who died in communities were often mummified with arsenic in order to be displayed in the traveling sideshow circuit. Arsenic was no longer used after the 1920s due to its toxicity. Chemical analysis can also be conducted on the hair of the mummy, which helps determine what type of diet the individual enjoyed, whether or not the individual smoked tobacco, and if there were any opiates in the system (Aufderheide 2003). The VE can assist in collecting these samples from within a bundle, further decreasing the chance of contamination. Ancient DNA Samples collected for ancient DNA (aDNA) need to be handled with great care. Radiography, fluoroscopy, or CT scan should be used to verify precise sampling site location. Additionally, sterile technique should be maintained. The VE is best used to visualize the target location with the sampling tool being introduced from another point of entry into the field of view, as in a laparoscopic procedure. Sampling tools for specimens intended for aDNA analysis should be instruments with a sheath or outer housing into which the sample can be retracted to protect it from contamination upon removal. Radiocarbon Dating Determining how old a mummy or artifact is in antiquity is a critical anthropological question. Sample attainment needs to be from an organic substance associated with or directly from the mummified individual. The VE is very useful in this procedure in that it can direct the researchers to obtain samples from within the mummy itself or from within the mummy bundle, avoiding contamination that may exist on surface structures. Archaeological Applications of Videoendoscopy Preexcavation Tomb Evaluation When planning an excavation, it is useful to know what to expect before opening a tomb or chamber. Is there a mummy in the tomb? Are there artifacts within the tomb or chamber? What positions and what relationships exist among tomb remains and objects? What is the overall condition of the mummy and the artifacts, if any? What conservation requirements can be anticipated? What excavation plan can be created? All of these questions can be addressed by introducing the VE into the tomb or chamber prior to its opening. The VE is best used with a far-focus lens in order to see as much of the tomb or chamber as possible. Often, a slave fiber-optic light guide and light source can be used to enhance illumination. Chapter 8 provides greater detail related to this VE application. Remote Imaging and Tomb Sampling Videoendoscopy can also be used to examine distant rooms within larger tombs or passages too narrow for researchers to fit through. If only a small opening exists, the endoscope can be introduced directly. There will be situations in which the space to be explored is large, and simply passing the VE into that space will not allow adequate visual documentation. In this case, an alternative approach can be adopted. The VE can be attached to a remote control vehicle and directed from outside the room or tomb (Figure 4.39). The VE of choice would need to be an industrial VE, which is available up to 60 ft in length. The disadvantages of this application would include the necessity of a reasonable opening for the remote-operated vehicle that can be of various sizes but is often at least approximately

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Figure 4.39  Remote-operated vehicle with 30 ft (9.14 m) videoendoscope and additional

illumination.

4 in. (10.16 cm) high by 6 in. (15.25 cm) wide. The power of the vehicle would need to be such that the drag of the trailing VE would not stall the vehicle. Samples can be drawn from the remote target locations through the VE and under VE visualization. Soil and air samples can be taken. With the VE images, preexcavation planning can be developed as well as conservation preparation. Conservation Preparation Mummies, artifacts, and skeletal material that have been placed in a museum on display or in the museum’s collection room require careful monitoring. Conservationists are concerned about any further deterioration of ancient material. Videoendoscopy in combination with conventional radiography can be employed to peer inside these objects or remains to determine if further conservation is required. The data can help determine what type of conservation may be necessary to stabilize the object or remains. Chapter 9 provides greater detail and case studies related to this VE application. Artifact Analysis Videoendoscopy can make a significant contribution to the analysis of ceramic artifacts. The VE can peer inside these ceramics, examine them for damage or cracks, and collect data that can help determine the method of construction. The degree of sophistication of construction says something about the degree of sophistication of the culture associated with the ceramics under study. Further, internal construction features can answer questions regarding trade among or between cultures and the evolution of ceramic technology. The VE can also be used to see what is placed inside the ceramic artifacts. If the ceramic was associated with a burial, what was important enough to be put inside? Samples of internal contents can be taken for chemical analysis, and a more complete understanding of the ancient people associated with these ceramics can be realized.

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Additional detail regarding the application of endoscopy in the areas of ceramics, artifact analysis, and tomb evaluation is provided in Section III. Case studies are included to illustrate these special applications. Emerging Applications: Endoscopic-Guided Light Reflectance/Absorption Analysis One of the problems associated with direct visualization via endoscopy when attempting to identify desiccated tissue or organ types is that desiccated tissue or organ morphology and anatomical orientation are typically altered, making identification difficult if not impossible. The application of light reflectance theory in this setting rests in the construct that all tissues and organs are chemically different and may absorb and reflect different wavelengths of the spectra. If the theory is correct, we hypothesized that various organs and tissues may have unique wavelength absorption or reflectance signatures. Mummified tissues and organs are subject to complete or partial desiccation, resulting in a loss of morphological characteristics. In addition, different embalming methods result in varied states of decomposition. Many cultures also practiced some form of tissue or organ removal and at times replaced those organs within body cavities. The impact of desiccation, state of decomposition, and organ removal or replacement all lead to a loss of anatomical landmarks often used to identify those organs (Aufderheide and RodriguezMartin 1998). Differentiation among organs through direct observation is greatly challenged by these variables. Current analytical methods used to differentiate tissue or organ remains include tissue and organ sampling or sectioning, rehydration for histological analysis, elemental and chemical analysis, and pathological and cellular analyses (Cockburn et al. 1998). Each of these methods alters any remaining internal anatomical context and is therefore a destructive technique. We conducted an initial project (Beckett et al. 2007a) whose objective was to determine if tissue- or organ-type differentiation could be made from nondestructive light reflectance or absorption methodologies when applied to tissues or organs from varied mummification and preservation methods. We established the following research questions: 1. Do different tissue types absorb or reflect light of varied wavelengths? 2. Do different organ systems absorb or reflect light of varied wavelengths? 3. If different tissue types or organ systems absorb or reflect light at varied wavelengths, is there variance in light reflectance signatures among mummified samples? Our methods, materials, and background research regarding light wave reflectance included an examination of the theory of light reflectance and absorption, which is grounded in color theory. Color theory demonstrates that the human eye is imperfect, in that it cannot differentiate among varied shades, and there are areas of the light spectrum that cannot be detected. What is absorbed and what is reflected is determined by the chemistry of the material. The application of light wave absorption and reflection is used in living tissue in medical science and analytical chemistry. One medical example is the varied light wave characteristics of hemoglobin (Hb) when compared to oxy-Hb (oxygen attached to the

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Hb molecule). Each state of Hb has different chemical characteristics. This is also true for alternate states of Hb such as carboxy-Hb, Met-Hb, Sulf-Hb, and deoxy-Hb (Ruppel 2005). Each substance can be differentiated from the others by using its unique light wave absorption and reflection signatures. This is accomplished by using an instrument known in medicine as a Co-Oximeter, which employs the spectrophotometric theory of light wave absorption. Light of varied wavelengths is sent through the sample. Those light waves that are not absorbed by the substance are measured by a photomultiplier and quantified. The absorbed wavelengths represent the specific absorption signature based on the chemistry of the substance under study. Another common application using reflectance is found in the reflectance pulse oximeter used to determine the degree to which Hb is saturated with oxygen. This instrument is placed on the forehead of newborns or infants. Light waves specific for the Hb molecule and for saturated Hb molecules are shown through the surface of the skin. The light waves that are not absorbed are reflected back to the photomultiplier from the frontal bone, and the determination of the percentage of Hb saturation is derived. As an integral part of our methods, we established our experimental design. A reflectance probe was used to both emit light waves and to collect the reflected nonabsorbed light waves. We first applied the reflectance probe to a preserved laboratory feline and examined the results. After examining the results, we then applied the reflectance probe to mummified tissues and organs under endoscopic guidance with radiographic positional correlation. Our subjects for this stage of the experimental design were a 100-year-old North American sideshow mummy and a 2500-year-old Egyptian mummy. We developed a plan to combine the technologies of the reflectance probe with endoscopy, which was used for reflectance probe guidance into internal body cavities, and radiography, which was used for probe positional documentation. We then collected and compared data derived from various organs and tissue types including cardiac, vascular, skeletal, renal, pulmonary, hepatic, gastrointestinal, and dental. We developed a logical uniform reporting and data comparison method as related to the reflectance data. We recorded the nanometer value at peak percent reflectance reading. We then refined our methods and resolved any technological or data collection problems. Finally, we repeated the experiment to assess the reproducibility of observed data and, ultimately, determine if there were any significant variations or correlations among and between subjects. In order to collect the required data, we employed three major technologies (Figure 4.40) in the course of this experiment:

Figure 4.40  Combined paleoimaging technologies. Shown here, from left to right, are standard radiography, reflectance instrumentation, and videoendoscopy system.

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1. Videoendoscopy was used for reflectance probe placement and location. Also, it was used to document the target organ or tissue and correlate the location with existing anatomical landmarks. We employed a fiber-optic VE, light source, camera control unit, and digital video data collection system. 2. Radiography was used to document probe location and correlate its position with anatomical landmarks using standard or instant film imaging and advanced imaging as needed. 3. Reflectance instrumentation was employed to collect reflectance data using a light guide or receiver probe, light source, and a spectrometer with a computer interface. The reflectance system was calibrated to absolute white and absolute black. As we began our experimentation, several application problems arose that required minor technological modifications. The first problem was keeping a standard and consistent distance between the probe and the tissue or organ target, thereby controlling for distance as a variable. To eliminate this variable, a 4 mm section on nonreflective quartz was affixed to the probe tip, ensuring a constant distance from probe tip to the target tissue or organ. Unfortunately, this modification using the quartz tip allowed ambient light contamination to enter the probe tip from the lateral aspect of the quartz, altering the reflectance data. To correct for this problem, we protected the lateral aspects of the quartz tip by using a thin rubber sheath, thus shielding the circumferential aspect of the nonreflective quartz and eliminating the ambient light contamination. The results from four separate experiments were promising. Experiment 1: Subject #1, Preserved Feline The organ systems of a laboratory feline were examined, using the reflectance technology. The reflectance characteristics of vertebra, diaphragm, kidney, lung, muscle, and neck muscle were examined. Data from the reflectance characteristics of the additional target organs of myocardium, tongue, and liver were collected. A composite of the peaks of the various tissues or organs were reported. Examination of the reflectance data collected demonstrated that each tissue or organ possessed varied absorption or reflectance signatures. The greatest variations were seen in the 300 to 400 nm range. When comparing the reflectance characteristics of the varied tissues or organs, it appears that each tissue or organ examined had both a general reflectance characteristic and a specific peak. Since the animal was preserved for laboratory dissection, the latex-embedded blood vessels (red for arteries, blue for veins) were also examined. The reflectance peaks of the latex, both red and blue, were both in the 300 to 400 nm range and seem to register once again near 800 nm. Experiment 2: Subject #2, North American Mummy (circa 1900) The subject was selected because of its high state of preservation, making its organ systems discernible. Additionally, access to internal thoracic and abdominal cavities and the oral cavity was present. Data regarding the reflectance signatures for the following organs/tissues were collected and compared: lung, liver, heart, intercostal muscle, skin, and tooth. Composite reflective signatures were constructed from the raw data in order to examine the signatures for variation. The results indicated that each organ possessed a unique reflectance signature. In this experiment, we also combined technologies to employ endoscopic guidance of the reflectance probe, to detect the impact of the endoscope guide light contamination on

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reflectance readings, and to verify probe position with radiography. As with all 2D radiographic exposures, two views were used to determine the location of a target within the 3D object. It is important to include these two views when reporting the reflectance raw data using anterior-posterior and lateral radiographs for probe location verification. Using the liver reflectance data, we also demonstrated the impact of light from the endoscope guide and found that it caused considerable light contamination, leading to the determination that reflectance measurements should be made after endoscopically positioning the reflectance probe and then turning the light to the endoscope light guide off. Reproducibility of the reflectance signature was also examined. We examined two separate lung reflectance signature graphs, with the second reading being taken after a rebooting and recalibration of the reflectance system. The data demonstrated a high correlation between the two measures. Experiment 3: Subject #3, Pa-Ib (2000–1500 BC) New Kingdom Period Egyptian Mummy Research related to Experiment 3 was conducted at the Barnum Museum, Bridgeport, Connecticut, to explore the portability of the reflectance technology and to collect data from a natron-desiccated mummy. Reflectance data were collected from the skin, tongue, tooth, the resin-coated wrappings, non-resin-coated wrappings, surface mold, and coffin lid pigments. Each tissue and organ produced a unique reflectance signature. Reproducibility was examined following rebooting and recalibration of the system, using the dental tissue of Subject #3, and was found to be highly correlative. Additionally, in Experiment 4, we made comparisons among common tissue types between Subjects #2 and #3, in an attempt to compare the impact of mummification method on reflectance signatures. Experiment 4: Comparisons between Experimental Subjects Comparisons of the reflectance signatures of the skin and tooth were made between Subjects #2 and #3. Additionally, a comparison of the reflectance signature of the tongue was made between Subjects #1 and #3. The reflectance signatures of the tissues of the human remains demonstrated high correlation between subjects, whereas the reflectance signatures comparing human remains to those of the feline demonstrated less correlation. Based on the results of the experiments, we came to several conclusions. The experiments of this study were designed to determine if we could distinguish between tissue or organ types by using light reflectance signatures. Our preliminary study suggested that there are variations seen in reflectance signatures among organ types and that those signatures are similar when collected from the same organ of different subjects that represent various mummification methods. Experiments also seemed to demonstrate that there is endoscopic light guide contamination when using the endoscope to guide the placement of the reflectance probe. When using these combined technologies, it is recommended that once placement is accomplished under endoscopic guidance, the endoscope light be turned off while reflectance measurements are made. Early data from this preliminary study suggest that there is good reproducibility when reapplying the reflectance probe to the same organ or tissue. However, a larger sample size is needed to make this determination with a greater degree of confidence.

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Figure 4.41  Reflectance report showing nanometer peak and reflectance contour with radiographs documenting reflectance probe position incorporated.

We also determined that the instrumentation is easy to apply in varied settings and is very portable. Reflectance technology may become a powerful tool along with videoendoscopy (Beckett and Conlogue 2006) and radiography in the on-site nondestructive data collection arsenal. Reporting is an important construct. Initially, this study was going to report the nanometer reading at peak reflectance for each organ or tissue analyzed. However, when the data were examined, it became apparent that the configuration of the reflectance curve was significant. We therefore recommend reporting percent reflectance peaks at specific nanometers, the contour of the reflectance data, and incorporate endoscopy and radiography images (Beckett and Conlogue 1998) to document probe position (Figure 4.41). This research is still in its infancy. We see the need for future studies to further examine the reproducibility of data through controlled bench top studies using both randomly selected mummified remains as well as remains derived from controlled organ or tissue mummification methods. We need to collect more data in order to conduct statistical analysis and power (Beckett and Conlogue 2006) analysis by increasing the N within various mummification categories. A larger and more varied sample selection would allow examination of the analysis of variance among and between mummification types and tissue types. We need to expand the study to examine varied tissues in varied environments. A specific research question may be to determine the reflectance signature, if any, of desiccated blood. Additionally, examination of the near-infrared and infrared ranges (nm) for variance in tissue or organ reflectance signatures needs to be conducted. As more research is conducted on light reflectance analysis, the VE will continue to complement these studies by playing a role in probe placement and guidance.

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Figure 4.42  (See color insert following page 12.) Theoretical application of endoscope light used to assess relative flat bone densities.

Potential Future Applications of Videoendoscopy: Transluminescence for Relative Density among Structures The steady and powerful light of the VE can be shown through structures such as bones, textiles, and ceramics. The translumination can be collected with a light meter outside of the target structure. The greater the translumination, the less dense was the target structure. Figure 4.42 presents several images of translumination of cranial flat bones using the VE. Density variations can be useful in differentiating among structures and objects as well as making cross-comparisons between study subjects. However, the issue of taphonomic change over time decreases the utility of this method. Although still experimental, transluminescence using the VE for density determinations may prove to be a useful data collection method. Alternate Light Endoscopy The VE light source can be modified to allow several filters to be placed in the light path. With alternate wavelengths of light shown through the VE, new data can be derived. Margins between and among varied tissues can be more readily identified under alternate light exposure. Varied tissue types can be more readily distinguished under alternate light visualization. Additionally, fungal contamination of mummified remains can not only be seen but also diagnosed under alternate light. Although still experimental, differentiating between organic and inorganic material may be enhanced under alternate light visualization. When the material is within the bundle or wrappings or within the mummy itself, the VE can provide the alternate light source delivery and visualization required.

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Endoscopy Summary and Future Applications In this chapter we have demonstrated the various ways in which videoendoscopy can be applied to anthropological and archeological research. The VE is a powerful imaging tool that when used together with other imaging modalities, specifically field conventional radiography, can bring meaningful data to the research project. In order to continue the validation of endoscopy in anthropological and archaeological research, procedural standards (Beckett 2007b) need to be considered. This will be discussed in Chapter 6. Future applications will be dictated by current paleoimaging research efforts and by creative thought regarding the use of VE.

References Aufderheide, A. C. and C. Rodriguez-Martin. 1998. The Cambridge Encyclopedia of Human Paleopathology. United Kingdom: Cambridge University Press. Aufderheide, A. C. 2003. The Scientiἀc Study of Mummies. Cambridge, U.K.: Cambridge University Press. Beckett, R. G. and G. Conlogue. 1998. Video Enhanced Fiberoptic Examination of Skeletal Material and Artifacts with Radiologic Correlation. In Papers on Paleopathology presented at the 25th Annual Meeting, March 31–April 1, 1998. Supplement to Paleopathology Newsletter, No. 102, June issue. Beckett, R. G., G. Conlogue, and R. Colton. 1999a. Endoscopic Evaluation of Segmented Sternum with Radiographic Correlation in a Peruvian Infant: Implications for Aging of the Individual. In Papers on Paleopathology presented at the 26th Annual Meeting, April 27–28, 1999, Supplement to Paleopathology Newsletter, No. 106, June issue. Beckett, R. G., M. McNamee, and J. Monge. 1999b. Endoscopic Evidence of Lymphadenopathy in a Mummified Peruvian Woman from Pachacamac. In Papers on Paleopathology presented at the 26th Annual Meeting, April 27–28, 1999, Supplement to Paleopathology Newsletter, No. 106, June issue. Beckett, R. G. and S. Guillen. 2000. Field Videoendoscopy—A Pilot Project at Centro Mallqui, El Algarrobal, Peru. In Papers on Paleopathology presented at the 27th Annual Meeting, April 11 and 12, 2000. Supplement to Paleopathology Newsletter, No. 110, June issue. Beckett, R. G., A. Bravo, G. Conlogue, and S. Guillen. 2003. Dead Men Breathing: The Prevalence of Intrathoracic and Extrathoracic Pulmonary Paleopathologies Among 83 Chachapoya Mummies, Leymebamba, Peru. In Papers on Paleopatholpgy presented at the 30th Annual Paleopathology Association Meeting, Tempe, Arizona, April. Supplement to Paleopathology Newsletter, June issue. Beckett, R. G. and G. Conlogue. 2006. Optimizing the use of Video Endoscopy in Bio-Anthropological Research. Paper presented at the New England Biological Anthropology Symposium, 2006. November 8, 2006 at Harvard University in Cambridge, Massachusetts. Beckett, R. G., G. Conlogue, and D. Henderson. 2007a. Light Reflectance Signatures among Mummified Organs with Endoscopic Guidance and Radiographic Correlation—A Preliminary Study. Paper presented at the 34th Annual North American Paleopathology Association Meeting, April, in Philadelphia, Pennsylvania. Beckett, R. G. 2007b. Paleoimaging—Standards for Endoscopic and Reflectance Applications in Anthropological Studies. Paper presented in live video conference with Forensic Anthropology & Bioarchaeology Graduate Program, October, for Pontifica Universidad Catolica del Peru. Lima, Peru. Bravo, A., G. Conlogue, R. Beckett, A. Staskiewicz, L. Engel, and S. McGann. 2003a. A Paleopathological Examination of Eighteen Mummies from the Church of the Dead, Urbania, Italy. In Papers

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on Paleopathology presented at the 30th Annual Paleopathology Association Meeting, Tempe, Arizona, April. Supplement to Paleopathology Newsletter, June issue. Bravo, A., G. Conlogue, R. Beckett, and L. Engel. 2003b. Exploring the Myth and Paleopathologies of Mummies from a Turkish Tomb, Amasya, Turkey. In Papers on Paleopathology presented at the 30th Annual Paleopathology Association Meeting, Tempe, Arizona, April. Supplement to Paleopathology Newsletter, June issue. Cartmell, L., G. Conlogue, R. Beckett, and P. Condell. 2003. The Paleopathology of a Mummified Arm among the “Big Four,” A Collection of Natural Mummies in Saint Michan’s Church, Dublin, Ireland. In Papers on Paleopathology presented at the 30th Annual Paleopathology Association Meeting, Tempe, Arizona, April. Supplement to Paleopathology Newsletter, June issue. Cockburn, A., E. Cockburn, and T. Reyman. 1998. Mummies, Disease, and Ancient Cultures, 2nd ed. Cambridge U. K.: Cambridge University Press. Conlogue, G., W. Hennessy, R. Beckett, and J. Posh. 1999. Nondestructive Analysis of Mummified Skeletal Remains: Approaches to Maximizing Imaging Outcomes (Introduction to the Seven Poster Symposium). In Papers on Paleopathology presented at the 26th Annual Meeting, April 27–28. Supplement to Paleopathology Newsletter, No. 106, June issue. Conlogue, G., R. Beckett, A. Bravo, R. Martin, and M. Smith. 2003. Anna of Kastl Germany; An Evaluation of the Princess Mummy. In Papers on Paleopathology presented at the 30th Annual Paleopathology Association Meeting, Tempe, Arizona, April. Supplement to Paleopathology Newsletter, June issue. Conlogue, G., J. Mansilla-Lory, R. Beckett, I. S. Leboreiro Reyna, and A. Bucher. 2004. A preliminary Radiographic Survey of Ten Mummies in Museo El Carmen in Mexico City, Mexico. In Papers on Paleopathology presented at the 31st Paleopathology Association Meeting Tampa, Florida, April 13. Published proceedings. Supplement to Paleopathology Newsletter, June issue. Conlogue, G., R. Beckett, A. Bravo, J. Taylor, R. Horne, R. Wade, L. Cartmell, U. Schmiedl, J. Jones, G. Stanley, N. Haskell, A. Aufderheidi, L. Engel, M. Smith, A. Cambell, A. Bucher, and S. Walbaum. 2005. Entertaining mummies: Embalming for the sideshow. J. Biol. Res. 80(1): 290–295. Conlogue, G., R. Beckett, J. Posh, Y. Bailey, D. Henderson, G. Double, and T. King. 2008a. Paleoimaging: The use of radiography, magnetic resonance and endoscopy to examine mummified remains. J. Rad. Nursing. 27(1): 5–13. Conlogue, G., R. Beckett, Y. Bailey, and J. Li. 2008b. A Preliminary Radiographic and Endoscopic Examination of 21 Mummies at the “Museo De Las Momias” in Guanajuato, Mexico and the Importance of a Team Approach to Image Interpretation. Paper presented at the 35th Annual Meeting of the Paleopathology Association, April 8–9, in Columbus, Ohio. Duclos, L., R. Beckett, S. Guillen, and G. Conlogue. 2000. Endoscopy as an adjunct to determining age at death in mummified remains. In Papers on Paleopathology presented at the 27th Annual Meeting, April 11–12, 2000. Supplement to Paleopathology Newsletter, No. 110, June issue. Freudenrich, Ph.D. C. 2001. How Fiber Optics Work.  At HowStuffWorks.com. March 6. http:// electronics.howstuffworks.com/fiber-optic.htm. Kim, S. B., J. E. Shin, S. S. Park et al. 2006. Endoscopic investigation of the internal organs of a 15thcentury child mummy from Yangju, Korea. J Anat. November; 209(5): 681–688. Nelson, A., G. Conlogue, R. Beckett, J. Posh, R. Chhem, E. Wright, and J. Rogers. 2007. MultiModality Analysis of Variability in Transnasal Craniotomy Lesions in Egyptian Mummies. Paper presented at the 34th Annual North American Paleopathology Association Meeting, April. In Philadelphia, Pennsylvania. Posh, J. and R. Beckett. 2000. A comparison of two nondestructive techniques for the evaluation of endocranial features—videoendoscopy and virtual fly through computed tomography. In Papers on Paleopathology presented at the 27th Annual Meeting, April 11–12. Supplement to Paleopathology Newsletter, No. 110, June issue. Ruppel, G. 2005. Manual of Pulmonary Function Testing. 8th ed. Chicago: Mosby.

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Tapp, E., P. Stanworth, and K. Wildsmith. 1984. The Endoscope in Mummy Research. In Evidence Embalmed, ed. R. David and E. Tapp, 65–77. Manchester, U.K.: Manchester University Press. Ventura, L., P. Leocata, R. Beckett, G. Conlogue, G. Sindici, A. Calabrese, V. Di Giandomenico, and G. Fornaciari. 2002. The natural mummies of Popoli. A new site in the inner Abruzzo Region (Central Italy). Anthropologia Portuguese. 19(2002): pp. 151–160.

Paleoimaging Standards

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Introduction In this section, we offer two chapters addressing potential guidelines and procedures for the systematic application of paleoimaging modalities. The guidelines and procedures described in this section are intended to help those involved in paleoimaging research projects and their colleagues make decisions on how to approach a specific research problem. Decisions regarding instrumentation and image receptor selection, projections, biopsy approaches, and other variables associated with paleoimaging are presented. The guidelines presented in this section also suggest a rationale for standardized reporting of paleoimaging procedures and data. Although selection of appropriate imaging modalities and standardized reporting are critical, this section recommends specific paleoimaging procedural standards as well. These procedural standards may serve as a set of initial instructions covering the features of paleoimaging methods that lend themselves to a definite pattern of application. The standardization of procedural practices is intended to increase the reproducibility of paleoimaging data collection in alternate settings without loss of effectiveness. Using a set of procedural standards can be an effective catalyst in driving both performance improvements and functional results. The standards offered in this section are not intended to be considered as directives, but rather as a common point from which quality improvements in paleoimaging applications can be built. Further, these standards and guidelines are offered as general frameworks and guides to good practice, with the expectation that individual paleoimaging research teams will use them as a basis to build their own procedures and practices specific to their institutions. Practices and procedures are often dictated by local resources, which may include the skills of the paleoimaging team members. As procedures are adopted and adapted throughout the paleoimaging research community, they can then be shared, moving the field of paleoimaging forward and improving the quantity and quality of the data collected. It is the purpose of this section to support the idea that paleoimaging as a focused specialty within mummy science should develop procedure-specific practice guidelines. Unlike the standards for the collection and documentation of anthropological data, no such guidelines for paleoimaging exist. Borrowing from medical professions, these practice guidelines may serve to help validate paleoimaging and its applications in mummy science studies. If developed, the practice guidelines need to be established with the global research community in mind in order to ensure that basic paleoimaging methods are applicable in a variety of research settings. Ideally, practitioners within the paleoimaging subspecialty area would establish the practice guidelines. These practice guidelines would serve to move the paleoimaging component of mummy science studies toward reproducible science.

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Each practice guideline developed may have the following minimal components: Procedure name/description/definition Settings Indications and objectives Precautions and/or possible complications/contraindications Potential outcomes Limitation of procedure/validation of results Assessment of need Assessment of quality of procedure, outcomes, and validity of results Resources required: equipment, personnel, and training Procedural monitoring Frequency of application Infection control/safety Culture-specific issues Finally, reporting and procedural standards are intended to guide those who use paleoimaging research in making responsible imaging choices. The reporting and procedural standards presented in this section are intended to promote researchers’ understanding and confidence in paleoimaging applications in anthropological and archaeological settings.

Radiographic Procedures and Standards

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Gerald Conlogue and Ronald Beckett Contents Introduction Recommended Reporting Standards for Radiographic Paleoimaging Applications Situational Variables Instrumentation Data Acquisition Parameters Special Procedure Protocol Data Collection Record Standards for Radiographic Paleoimaging Procedures in Anthropological and Archaeological Research Visual Inspection Establish Research Objectives Photography Consideration of Complementary Modalities Initial Radiographic Survey Survey of Body Cavities and Artifacts Refinement of Imaging and Target Analysis Procedural Documentation Postprocedure Conference and Data Review Recommended Radiographic Exposure and Application Considerations Conventional Radiography Computed Radiography Multidetector Computed Tomography (MDCT) Magnetic Resonance (MR) Conclusion Reference

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Introduction Ever since their discovery, radiographic techniques have been used to see what once could not be seen in anthropological and archaeological research. Paleoimaging as a discipline is based on the foundation of various research reports and presentations at scientific meetings. Too often, these reports do not provide future researchers with enough information about the imaging project that would allow reproducing the application. Further, reports that suggest the imaging data did not yield usable information or that misinterpretations were made from imaging data are often the result of inappropriately applied data collection variables. In this chapter, we offer a standardized method for radiographic paleoimaging reporting 233

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and procedural applications. These recommendations are based on years of focused practice in radiographic paleoimaging research and are intended to promote common practice in radiographic paleoimaging. If common practices are adopted, field and laboratory research may become more productive and efficient, and the collection of usable data less prone to misinterpretation will be enhanced. With common practice in radiographic paleoimaging reporting and procedures, studies will be more reproducible and therefore serve to educate current and future paleoimaging scientists as well as other professionals involved in anthropological and archaeological research. Much of the content of this chapter is derived from a presentation made at the at the VI World Congress on Mummy Studies, held in February 2007 in Teguise, Lanzarote, Canary Islands, Spain (Conlogue et al. 2007).

Recommended Reporting Standards for Radiographic Paleoimaging Applications Situational Variables When conducting field radiography, many variables influence the manner in which the paleoimager approaches the research task at hand. If another researcher is to fully understand how the data were collected, it is important to report as much about the physical setting as possible. Factors such as how much workspace there was, what were the temperature and humidity variables, and what the setting was (indoor, outdoor, imaging center, field, tomb, cave, etc.) provide information that can explain associated problems and possible solutions for the imaging project. For example, a humid environment may impact the way in which instant film is processed and would be valuable information for other researchers. If a researcher devised a way to overcome this challenge, the report should reflect those problem resolutions. As much information as possible about the setting and context should be reported, supported with photographic documentation. If the work is being conducted in a tomb, the specific tomb characteristics should be noted, including conditions influencing tube and image receptor placement. The overall project goals and physical descriptions of the subjects under investigation should be reported. These data will also provide direction to the imaging study. Instrumentation It is imperative that the instrumentation characteristics be reported in order to understand both how the data were collected and any limitations imposed on the study due to the technology used. More importantly, without the information, it may not be possible to reproduce the results. Included in the narrative should be a description of the x-ray unit and electrical power supply. A complete account of the type of image receptor is extremely important. If conventional film was the recording media, the report must provide information such as its manufacturer, specific type, and expiration date. Taking into consideration the security issues we face in the 21st century, it would be particularly helpful to know how the film was obtained and transported to the site where it will be finally used. For example, if it is transported in checked baggage, it will probably go through a radiographic screening process. Also important is a description of how the film was used. For example,

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notation of how the film was loaded into a nonscreen holder or the use of a cassette with an intensifying screen gives detail to those reading the report. If the latter was the case, the description should include the screen manufacturer and relative screen speed. Finally, a complete explanation of how the exposed film was processed must be included. If it was manual processing, the manufacturer and specifications of all the chemicals used must be included. If it was automatic processing, there should be a description of the normal operation of the facility. For example, in a major medical center, 50–100 additional films put through the processor will not make a difference. On the other hand, the same volume of films put through the processor in a rural center may exceed the number of films processed in a month and have a negative effect on the resulting image quality. If instead of film, a digital image receptor, either computed radiography (CR) or direct digital radiography (DR), was used, less information will be needed. However, the manufacturer, the algorithms employed, the “S” number, and depending on the system, the “G” or “L” values must be included in the narrative. Supportive technologies should also be described and documented with photography. Notations about the tube support system used and the image receptor support should be included in the report. Also of importance are the workflow characteristics employed in the study. Future researchers would benefit from ideas regarding efficient throughput methods developed and adapted to the study at hand. Data Acquisition Parameters This section of the paleoimaging report should provide the technical variables or settings used for each radiograph produced. In this portion of the report, each radiograph is numbered sequentially with new subject lines interjected as the study material flows through the imaging workstation. Minimally, those data that need to be reported include exposure variables such as Source-to-image receptor distance (SID), kVp, mAs, and the focal spot size. Positioning variables should also be noted, such as anterior-posterior (AP), posterioranterior (PA), lateral (L), oblique (Obl), as well as any additional projections required to collect the desired images, such as a Towne’s projection to demonstrate cranial synostosis. Special Procedure Protocol Often, after the initial radiographic survey, structures may be detected that require greater scrutiny. Complementary technologies such as endoscopy and/or biopsy may be employed to attempt to capture additional data. The report should contain information including the aforementioned data acquisition variables used to document endoscope placement. Additionally, if a biopsy or artifact retrieval procedure is to be conducted, radiographs taken before and after the procedure should be reported. Any special exposure variables such as nonscreened extended exposures or exposures using multiple nonscreen image receptors should be reported in detail. Data Collection Record In an attempt to standardize data reporting from radiographic paleoimaging procedures in anthropological and archaeological settings, we offer a data collection instrument discussed in Appendix A. The instrument is designed as a data collection tool as well as a

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guide to assist researchers in thinking more globally about the procedures. When a manuscript is submitted for publication, the radiographic data collection instrument will serve as a clear record of how the paleoimaging procedures were conducted, in what setting, with what instrumentation, and with what results. If these procedural points are in turn published, other researchers can better reproduce the applications in alternate settings. Page one of the data-recording form provides a uniform system of reporting situational and identification variables, instrumentation and image receptor descriptions, and initial observations. A location for recording the study objectives is also provided, followed by the main data-recording chart. Note that there is a place to confirm that a photograph was taken from the perspective of the x-ray tube projection. Page two continues the data-recording chart and provides space to describe any special procedures conducted during the study. A final section asks the paleoimager to comment on the overall efficacy of the study, and note its limitations and future study plans or objectives. After film interpretation, decisions regarding advanced imaging can be reported in the overall commentary section. The uniform data-reporting tool has the potential to provide the researchers with a clear record of the radiographic paleoimaging procedures as related to the study. The record can provide data for manuscript preparation and serve to guide future researchers as to how the data were collected, what problems arose, and the resolution to those problems. Any limitations to the study based on such variables as technology can be reported, which will help future study planning processes. Standards for Radiographic Paleoimaging Procedures in Anthropological and Archaeological Research If radiography is to reach its full potential as a tool for data collection in anthropological and archaeological research, researchers must attempt to standardize application variables of this modality. If radiographic methods are misapplied and reported, progress in the development of radiographic paleoimaging may be hampered. With the experience gained regarding the procedural aspects of this modality, we recommend a unified approach. The authors recommend the following procedural framework as a methodological standard for radiographic applications in anthropological and archaeological research. Visual Inspection Beginning with the physical exam, the paleoimager is allowed time to become familiar with the challenges associated with the subject, human or nonhuman, under study. It is imperative that the paleoimager be familiar with the varied possible methods of mummification. Instrumentation and exposure variables are based on perceived densities. Different mummification methods provide different imaging challenges. For example, natural mummification, which occurs naturally or without any active attempt at mummification, may render a body with few or no internal organ systems present. Additionally, observing the position in which the individual was interred will make the paleoimager aware of the possibility of superimposition of images and help in the strategic planning of the study. Knowledge of the enclosure used to bury the remains is also important. An urn burial presents a different imaging challenge than does a textile-wrapped mummy or one in a coffin. An artificially prepared mummy, one that was intentionally prepared for

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preservation, poses unique imaging challenges as well. Egyptian mummies, for example, were often coated with resin, and that resin was often introduced into body cavities, markedly increasing the density. The paleoimager should make a cursory assessment of the integrity of the subject to ascertain the feasibility of radiographic examination. Photographic documentation of features of interest discovered during visual inspection is required. During the initial visual inspection, the paleoimager may establish the instrumentation strategy and the radiation protection plan, which will be dictated by the subject, the physical space, and the research objectives. Establish Research Objectives Each imaging project should begin with a general radiographic survey of the study subjects as its initial objective. The analysis of the data derived from this broad survey will direct further imaging goals. As stated in Chapter 2, during the initial survey, four fundamental objectives should be addressed. The first is that of an assessment of the condition or integrity of the subject. In the case of human remains, the articulation status of the skeletal system should be examined. Any surface disruptions in the integumentary system should be noted as well as the overall condition of the mummy wrapping, if any. If the subject is an artifact, examining the radiograph for fracture lines is crucial to determining the condition of the object. From these data, decisions regarding the imaging plan can be made. The other fundamental objectives, such as age at the time of death, sex determination, and dental status, may all be addressed during the initial survey. Upon completion of the initial survey and analysis of the radiographic images, refined objectives can be established and addressed. Imaging for evidence of paleopathologies as well as documentation of specific cultural practices, such as burial practices, mummification methods, cultural cranial modification, and documentation of ancient medical practices, can be accomplished as the case and previous images direct. Objectives related to imaging for artifact analysis or retrieval and target localization for biopsy may be addressed as well. These artifacts may be crucial for establishing an approximate temporal context associated with the remains. Some of the refinement objectives may not be able to be met. In many cases, the mechanism of death cannot be determined; however, it should always be considered an objective of all imaging studies involving human remains. Moving from the fundamental to the refinement objectives provides an ordered system of analysis and maximizes the potential outcomes of the study at hand. By reviewing the radiographs that have addressed the fundamental objectives, refinement objectives can be ordered and sequenced according to initial interpretations. The objectives provide structure to the imaging project and serve as a guide, possibly improving both efficacy and efficiency. Photography Photodocumentation is a critical component of the imaging procedure. Photo documentation should provide records of the subject as well as the context in which the study is being conducted. Any environmental factors that may influence the study should be documented. It is important to document the instrumentation setup, including the tube support, examination stage, and image receptor support. Any unusual utility hookups need to be documented. Also critical to the study is a photograph of the subject from the perspective of the x-ray tube projection angle. These images will help observers of these data better

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understand what is imaged in the radiograph, as many researchers are not accustomed to viewing radiographic images. Consideration of Complementary Modalities Following the visual inspection and building on what prior information was available regarding the study subject, a conceptual plan for using complementary paleoimaging modalities should be considered. These considerations will necessarily be based on what may be available. In field settings, endoscopy may be the only additional modality applicable. If the research is being conducted nearer to a village, town, or city, paleoimagers should make themselves aware of what the potential is for advanced imaging, such as computed tomography (CT) or magnetic resonance (MR) scans as they relate to the current study. Initial Radiographic Survey The ideal survey would include head-to-toe imaging using both AP and lateral. Although film quantity and cost may be factors in the particular study, we recommend the following minimal triage projections:

1. Lateral skull 2. AP and lateral thorax 3. AP and lateral abdomen 4. AP and lateral pelvis 5. Document position of endoscope (when used)

With unlimited resources, a radiographic survey of skeletal remains should further include, other than the previously described skull projections, AP and lateral views of all the long bones. Even if the external features of bones may appear normal, the trabecular pattern within the metaphyses in the proximal femurs, distal radii, and calcanii can provide valuable insights into bone health. For example, fewer and thicker trabeculae may indicate osteomalacia. A lack of evidence of biomechanically influenced trabeculae suggests possible disuse osteoporosis. Increased cortical thickness under sites of muscle origins and insertions demonstrates repeated activity over a prolonged period. These data in turn will serve to direct the remainder of the imaging study. Survey of Body Cavities and Artifacts Following the initial survey, the images should be reviewed systematically. Although there are many recommended approaches, the cranial to caudal system ensures that all cavities and extremities are reviewed. What follows is a presentation of those features within each cavity that should be examined. Please note that this list represents the minimal assessments. Additional assessments will be dictated by the research goals. a. Cranial cavity i. Presence, location, and characteristics of residual brain tissue (consider burial position, organ removal, state of preservation) ii. Condition of the internal cranial table (consider lesions, hammered copper appearance as evidence of increased cranial pressure) iii. Condition of the meningeal grooves (consider pattern, frequency, direction as related to anomalous findings)

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iv. Configuration and relative depth of the venous sinuses (consider the impact of cultural cranial modification) v. Condition of the crista galli and cribriform plate of the ethmoid bone (consider route of brain tissue removal in some forms of mummification) vi. Condition and configuration of the sella turcica (consider pituitary lesions, gigiantism versus acromegaly) vii. Characteristics of suture fusing pattern (consider age at time of death, cranial synostosis, Normian bones) viii. Presence of organic or inorganic matter (consider cranial vault treatment, cranial vault contamination) ix. Examine cranial bone thickness/porosities/hair on end (consider pathologies, marfans, porotic hyperostosis, anemias) x. Presence and location of abnormal openings into the cranial vault, such as fractures and trephinations xi. Characteristics, typing, and impact of cultural cranial modification (consider extent, tabular, annular, biological impact) xii. Sex determination characteristics (consider browridge, occipital protuberance, mastoid process, robustness) xiii. Anomalous findings b. Oral cavity i. Presence of oral tissues (consider exposure variables) ii. Determine the degree of dental attrition/inventory (consider alternate radiographic projections) iii. Determine tooth loss pattern (consider alveolar status, pre- or perimortem) iv. Presence and extent of caries v. Evidence of dental modifications (consider fillings) vi. Artifacts as offerings (consider metallic, nonmetallic) vii. Assess degree of surface wear (consider environmental context, sand in food, age) viii. Examine for indicators of disease (consider exposed roots, mandibular or maxillary erosions, impactions) ix. Age at time of death (consider dental growth standards, surface wear) x. Mandibular assessment (consider: temporomandibular joint [TMJ], trabeculae patterns) xi. Cervical vertebral region (consider fractures, hyoid bone, arthritic changes) xii. Anomalous findings c. Thoracic cavity i. Assess the state of preservation (consider thoracic organs and structures, mummification method, bony articulations) ii. Examine any calcified lesions or target structures (consider lymph node involvement) iii. Internal thoracic structural status—ribs, vertebrae, etc. (consider premortem versus perimortem fractures, arthritic changes, Pott’s disease, scoliotic conditions, genetic/congenital anomalies, diffuse idiopathic skeletal hyperostosis [DISH]) iv. Presence of pulmonary- or cardiac-associated calcifications (consider atherosclerosis)

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v. Presence and characteristics of artifacts vi. Anomalous findings d. Abdominal cavity i. Presence and condition of abdominal organ remnants ii. Descending aortic calcifications iii. Renal stones iv. Gall stones v. Lesions vi. Examination and characterization of any artifacts or artificial packing material vii. Lumbar vertebrae assessment including L5–S1 (consider fractures, arthritic changes, fusions) viii. Anomalous findings e. Pelvic cavity i. Presence and condition of pelvic organ remnants and/or evidence of pregnancy ii. Examine bony structures for aging indicators iii. Pelvis fractures iv. Bladder stones v. Hip conditions (consider fractures, congenital hips, disarticulations, arthritis) vi. Examination and characterization of any artifacts or packing material vii. Coprolite material viii. Anomalous findings f. Extremities i. Fracture patterns and healing patterns (if any) ii. Evidence of repetitive biomechanical stress (consider muscle group insertion points) iii. Aging indicators (consider carpal bone development, epiphyseal fusion patterns) iv. Presence of arthritic changes v. Presence of indicators of paleopathologies (consider growth arrest lines, bone lesions, calcinosis cutis) vi. Anomalous findings g. Artifacts i. Presence and location of artifacts (consider in the wrappings/textiles, within the body) ii. Characteristics of artifacts (consider metallic, ceramic, unknown) iii. Examine for any associations with other artifacts Refinement of Imaging and Target Analysis In many cases, a specific area or artifact will present itself in the initial data requiring refinement of the image in order to provide information regarding its characteristics and precise location. This procedural step may be conducted on targets identified on radiographs, such as calcified lesions, specific arthritic changes, specific dental features, artifacts, cultural modifications, burial practices, mummification methods, and bony

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fractures. Refinement may require alternative imaging projections that will free the target object from the problems of superimposition. Altered exposure settings, too, may be required to better image the target structure. Confirming pathological changes is conducted in this procedural step. This step may also be used to support biopsy efforts and artifact retrieval by using the radiographs for localization as well as pre- and postprocedure documentation. Procedural Documentation All techniques and results should be recorded in a manner that provides enough detail to allow reproducibility. A systematic recording instrument similar to the data-reporting form presented earlier in this chapter should be adopted for this purpose. Postprocedure Conference and Data Review Data collected from the radiographic study should be reviewed with all members of the research team present. Whenever possible, the “team” would ideally include a physical anthropologist, a bioanthropologist, a bioarchaeologist, a radiologist, a forensic odontologist, a paleopathologist, paleoimagers including the photographer, and other individuals who may contribute to the findings. A cultural and/or forensic anthropologist would add greatly to the team. Data from additional modalities, if used, should be included in the postprocedure conference. Considerations regarding the application of advanced imaging modalities should be discussed weighing carefully the cost/benefit ratio of such efforts. The consensus and future research questions arising from the conference should be recorded with manuscript preparation in mind. If procedural and data-recording standards for radiographic paleoimaging are adopted, more focused research efforts can be planned and more complete data may be acquired. With proper information being reported in the literature, less time may be spent in the field reinventing methods or applications. In keeping with this construct, recommended radiographic exposure and application variables will be presented.

Recommended Radiographic Exposure and Application Considerations Conventional Radiography A maximum kVp of 55 yields optimal presentation in desiccated mummified remains, and conventional radiographic film is the image receptor. A source-to-image receptor distance (SID) of 40 in. is the minimum distance required to cover a 14 × 17 in. (35.6 × 43 cm) image receptor. If kVp and SID are constant, the exposure time becomes the major variable requiring manipulation to acquire proper images. The image receptor should be placed as close to the subject as possible to minimize magnification on the resultant image. Whenever possible, if conventional film is the recording media, nonscreened imaging should be used as it decreases contrast, increases soft tissue visualization, and provides increased detail. All images should be reviewed with a radiologist to determine further imaging objectives.

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Computed Radiography Because of the inherent characteristics of the system, the kVp needs to be increased to a minimum of 70 if CR is employed. To provide adequate coverage of the image receptor, the same SID as described earlier would be required. Although it is frequently stated in the literature that when using CR the mAs should be reduced by 50% from the conventional radiographic technique, this has not been our experience. Even though the kVp is increased over the setting noted previously, the initial mAs value should be at least that used for a conventional screen/film system. A good starting point for mummified remains at a 40 in. (100 cm) SID would be 70 kVp at 10 mAs. There are two principal advantages of CR. The first is the elimination of wet processing and everything associated with the need to handle and transport the chemicals. The second is the ability to postprocess the image without having to take additional exposures. The latter not only reduces the amount of time required to complete the study but also reduces the radiation exposure to those involved in the project. A major disadvantage with the medical CR systems is that the algorithms were developed for hydrated living bodies. The authors suggest that a more successful approach may be to use a nonmedical CR system and apply various industrial algorithms during postprocessing to produce the most detailed image. Multidetector Computed Tomography (MDCT) When advanced imaging with MDCT is appropriate, using a lower kVp setting, such as 80, will provide adequate penetration while reducing the heat load of the x-ray tube. Referring back to the initial film or CR images, specific regions that require CT study should be identified. Thick slices, no smaller than 3 mm, should be collected and then reconstructed to submillimeter thickness (0.7–0.5 mm) through the areas of interest. As analysis of the data begins, view the axial sections, starting with a bone algorithm and working through tissue algorithms as required. Next, reformat the data into coronal and then sagittal sections using about 1.5 mm slices. If a tissue sample is required, establish the target location on the axial sections and conduct a CT-guided percutaneous biopsy. All data should be saved in the Digital Imaging and Communications in Medicine (DICOM) format, which will allow data postprocessing on an independent console (Vitrea®) or a laptop computer (Osirix®). During postprocessing, collect data, such as measurements of lesions, artifacts, or foreign bodies, and assess the CT value region of interest (ROI) of organ remnants, resins, apparent clots, etc. When called for, employ specialized protocols, such as Dental CT and 3D reconstructions of regions or structures of interest. When using 3D reconstruction, experiment with various algorithms to acquire the desired data. When using CT scans for 3D reconstructions, postprocessing should be conducted by a skilled radiographer. 3D images will probably be less diagnostic than the section examinations. It is recommended that the sectional studies, axial, coronal, and sagittal, be the primary CT approach. If 3D reconstruction is to be employed, it should be directed toward answering specific questions. For example, a 3D reconstruction can be used to more precisely evaluate openings into the cranial vault that were used for removal of brain matter in Egyptian mummies. 3D reconstructions may be used to determine the sex of the individual if direct observation is not possible due to resinous wrappings covering and adhering to the pelvic area. The 3D reconstruction is very helpful if the axial CT image showing the subpubic angle was not diagnostic for sex in cases where the pelvis configuration was distorted during or after mummification.

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Magnetic Resonance (MR) When using MR, the best approach seems to be a T1-weighted (TR < 400 ms, TE = 3–5 ms) scan in spin echo setting starting with thick slices at around 5 mm. Recall the discussion in Chapter 3 regarding the magnet tuning procedure using saline IV bags. MR may give data regarding residual fatty deposits within apparently desiccated remains.

Conclusion The use of radiographic modalities in anthropological studies is well documented in the literature and has earned its place in the paleoimaging data collection arsenal. The instrumentation flexibility of conventional radiography demonstrates its versatility in a variety of contexts, including fieldwork, laboratories, museums, and medical facilities. The authors are certain that with a focused effort, CR will be incorporated into paleoimaging as well. Advanced imaging modalities, such as CT and MR, need to be considered on a cost/benefit basis. The potential cost is not necessarily monetary but more importantly, the cost may be damage to the mummified human remains or artifacts during transport. If research questions can be answered in the field using complementary field paleoimaging instrumentation, advanced imaging may not be required. When using advanced imaging, radiographers skilled in gathering the desired data are a key factor related to the value of the data obtained. Experience with mummified remains or other nontraditional imaging projects on the part of the radiographer will allow for creative manipulation of the instrumentation and advancement of CT and/or MR as data collection tools for anthropological and archaeological research. Finally, to enhance reproducibility of research associated with radiographic applications in anthropology, standards for procedural aspects and data recording need to be adopted. In this fashion, through standards of recording and procedural application, the role of radiography, particularly in field studies, can be further expanded to provide verifiable data to scientific endeavors.

Reference Conlogue, G., J. Posh, R. Beckett, and R. Lombardo. 2007. The Value of Multimodality Paleoimaging for Establishing Baseline Standards for the Evaluation of Mummified Human Remains. Paper presented at the VI World Congress on Mummy Studies, February, in Teguise, Lanzarote, Canary Islands, Spain.

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Endoscopic Procedures and Standards Ronald Beckett and Gerald Conlogue Contents

Introduction Reporting Standards for Endoscopic Paleoimaging Applications Situational Variables Route of Entry Instrumentation Radiographic Correlation Data Acquisition Media Biopsy and Sampling Special Procedures Specific Reporting of Light Reflectance Experimentation Data Collection Record Procedural Standards for Endoscopic Paleoimaging in Anthropological and Archaeological Research Conclusions Reference

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Introduction Given the contribution made by endoscopic applications in the bioarchaeological setting and the increasing reference to endoscopy in the related literature, it seems imperative that standards for procedural and study results be established. One of the hallmarks of a well-written research report is that from the information provided, other researchers have enough information to reproduce the study in similar or alternate research settings. Many studies simply state that they employed endoscopy in the study. That information alone leaves much to the imagination and is not capable of being reproduced. Information regarding the research setting, the endoscopic entry route, the instrumentation characteristics, and any modifications that had to be made during the procedure are examples of data that would help future scientists reproduce the study. Additionally, these data may allow other researchers to think more creatively about endoscopy applications and move endoscopic research in anthropology and archaeology forward. With standard reporting, scientists can better reproduce the applications in alternate settings without introducing a variable, which may alter the outcome of a new study. In an attempt to direct the application of endoscopy in anthropological and archaeological research and to establish a uniform approach to these applications, we have called upon our experiences and what we have seen in the literature to recommend guidelines regarding what and how to report both procedural variables and the data collected during 245

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a given study. In doing so, we intend to call attention to the broader application potential of the varied endoscopic procedures and applications described in Chapter 4 of this book. What follows is a discussion regarding standards for conducting and reporting endoscopic procedures and data collection in anthropological and archaeological research. Much of this chapter is based on a presentation given at the VI World Congress on Mummy Studies held in Teguise, Lanzarote, Canary Islands, Spain, in February of 2007 (Beckett et al. 2008).

Reporting Standards for Endoscopic Paleoimaging Applications Situational Variables Collecting as much demographic and descriptive data as possible is necessary in order to identify the specific characteristics of the mummy under investigation. The mummification technique, bioarchaeological setting of the study, contextual setting, and physical findings should all be recorded and photodocumented, as these and other variables will impact the choices regarding endoscopic applications. The project goals should be clearly reported. Reporting whether the endoscopic procedure is to be for a general survey, specific artifact analysis, target biopsy, or an exploratory procedure clarifies the intent of its application. Route of Entry Introduction of an endoscope requires an entry point to achieve body cavity access in mummified remains or access to artifacts, tombs, or other enclosed spaces. In the case of mummified remains, this opening may be anatomical—a product of initial stages of decomposition, taphonomic changes over time, or it may be artificial in nature. The route of entry must be described in detail, including any challenges associated with this particular approach and how those challenges were addressed. The entry route must also be photodocumented with scale prior to and during endoscope introduction. These data will allow future researchers to perhaps find an entry point that may not be obvious. Instrumentation Reporting the type of instrumentation used in the study is also critical for future researchers to understand in what manner the data were collected. Instrumentation characteristics such as type of scope, industrial or medical, videoscope, borescope, scope diameter, scope length, lens type, illumination settings, and other variations will all help readers of such reports better understand the method of data acquisition. Additionally, reporting in this manner will share instrumentation variations that are perhaps not envisioned by researchers less familiar with the technology. Reporting these technological variations will clearly increase the potential of reproducibility and perhaps enhance the data collection process in subsequent studies. Radiographic Correlation Whenever possible, a critical part of the endoscopic procedure should be radiographic correlation. The radiograph will document the location of the endoscope within the enclosed area, be it a body cavity or a coffin. Two views are often necessary in the field in order to

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determine spatial relationships and endoscope location. Reporting that the radiographs were done and including copies of those images in the endoscopic report are essential for reliable data interpretation. If advanced imaging is employed, those methods should also be reported with supporting images verifying endoscope location. CT scans may give a more precise spatial relationship of the endoscope within the target object or mummified remains. Fluoroscopy is an excellent adjunct to the endoscopic procedure, giving the endoscopist a real-time view of endoscope direction and location. When fluoroscopy can be employed, moving images should be captured to better describe the endoscopic procedure. Although advanced imaging provides excellent correlation regarding endoscope position, it is not practical in the field since its size and weight prohibit easy transport to remote settings. Standard radiography is easily applied and can provide excellent correlation of endoscope position. Regardless of imaging method, endoscope positional verification is critical to the documentation of either what is being viewed or from where within the subject a sample was taken. Data Acquisition Media Another important factor to report is the data acquisition media used to record collected data. Some of the possible systems include digital videotape, digital videodisks, computer hard drive, Secure Digital (SD), and compact flash technology, optical disks, and objective eyepiece photography. Images can now be captured in High Definition as well. Older technologies such as Hi8mm tape-type video may still be available for data acquisition. The resultant resolution varies among the types of data collection media used in a given study. Knowing what media were used in a particular study can tell future researchers about their data collection media selection. If a gross overview of the target object or mummy is the goal, resolution may be secondary to the broader scope of the project. On the other hand, higher resolution is critical in assessing the finer details of anatomical or pathological structures and construction features of artifacts. Since researchers using endoscopic methodology on any given project have no idea of what data they may encounter, a rule of thumb regarding data collection media would be to use the media that offers the highest possible resolution image. In this way, a more detailed analysis of the data can be done and the potential for misinterpretation can be reduced. When the type of media used in an endoscopic research project is reported, other researchers can save time by not using substandard media from the onset of their project. Biopsy and Sampling If a biopsy is conducted via the endoscopic procedure, the biopsy site with as many specifics as possible needs to be reported. It is imperative that any biopsy conducted have clear potential for success and subsequent analysis. Any biopsy procedure must clearly fit within the research objectives and protocols. Recording the biopsy objectives assures other researchers that the procedure had a real purpose for the collected material in the study at hand. If the biopsy is scheduled for ancient DNA (aDNA) analysis, the extra precautions regarding sterile collection should be recorded. Radiographic location documentation is crucial to the biopsy procedure. Radiographs should be taken before and after the biopsy. Reporting the sample characteristics, such as volume and

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physical description along with photographic documentation, aids future researchers and enhances the potential for comparative analyses. The biopsy instrument should be described. When the biopsy results have been reported, the information should be included on the endoscopic data reporting form in order to correlate the biopsy site, biopsy method, biopsy material characteristics, endoscopic images, and radiographic findings with the biopsy results. A graphical representation or sketch of the biopsy approach should be included in the report. When endoscopy is used for artifact retrieval from within mummified remains or any enclosed space, the same procedural reporting method as described for a biopsy should be followed. Specifically, reports regarding artifact retrieval procedures should include the following: the location of the artifact, the instrumentation used to identify and retrieve the artifact, that radiographic verification before and after retrieval was conducted, and that photographic documentation of entry point and of the retrieved object was accomplished. A graphical representation or sketch of the artifact retrieval route should be included. With this detailed documentation, the chances for reproducibility of the procedure is more probable. Special Procedures Any special procedures conducted during the course of the endoscopic procedure should be reported in as much detail as possible. Some of these special procedures may include alternate light application, light reflectance probe guidance, and artifact analysis or removal from a mummy bundle, coffin, or tomb. Specific Reporting of Light Reflectance Experimentation If light reflectance is part of the experimental protocol, any technical modifications required should be noted. Photographic documentation and radiographic correlation should be a standard part of the procedure and must be reported. If the endoscope was used for reflectance light probe insertion, data should be collected with the endoscope light guide off. Data to be collected and reported should include the contour of the reflectance tracing. Reporting data in this manner allows for archival database development as well as reproducibility of technique and results. In this manner, the applicability and utility of light reflectance methodologies can be further assessed.

Data Collection Record In an attempt to standardize data reporting from endoscopic procedures in anthropological and archaeological settings, we offer a data collection instrument titled “Recording Form for Endoscopic Examination of Mummified or Skeletal Remains” (Appendix B). The instrument is designed as a data collection tool, as well as a guide to assist the endoscopist in thinking more globally about the procedure. When a manuscript is submitted for publication, the endoscopy data collection instrument will serve as a clear record of how the endoscopic procedure was conducted, in what setting, with what instrumentation, and with what results. If these procedural points are in turn published, other researchers can better reproduce the applications in alternate settings.

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On the first page of the aforementioned recording form (see Appendix B), spaces are provided to enter situational variables related to the current study. The form includes a space to enter data regarding the site and work setting, condition of the remains, and initial goals for the endoscopic procedure. At times, initial radiographs dictate the specific objectives of the endoscopic procedure. A specific location is provided to record those initial radiographic findings. Additionally, there is space to record the instrumentation characteristics, including, but not limited to, type of scope, diameter, length, lens type, and recording media. Following the record of the situational variables and instrumentation used, a data record section is provided that allows the researcher to record the procedure in the order in which the data was collected. The endoscopist may record the cavity that they are currently examining using the suggested abbreviations provided, the access route into that specific cavity, whether or not a radiograph has been taken at that site, a record number as related to the data collection media employed, a description of their initial findings, and a notation of any special procedures conducted. Additional abbreviations are suggested to reduce physical writing and to provide a standard by which procedures are referred to. The endoscopist is encouraged to photodocument entry points and provide an anatomical sketch of those entry points identified by data collection number and the cavity currently under study. Anatomical charts may be provided with the form to help illustrate those entry points. These charts may also be used to indicate the location of any artifacts discovered within the mummified remains or within a mummy bundle. The second page of the form provides spaces to record data as they relate to any biopsy procedures conducted. Reporting the instrument used for biopsy or for artifact retrieval and descriptive data regarding the material collected is encouraged by the form. The biopsy number, the location and probable tissue or organ biopsied, and the physical description and approximate volume of the biopsy should all be recorded. Photography of the material with scale should be conducted and recorded as well. “Before” and “after” radiographs should be included in the procedure comments at the end of page two of the form. It is important to have an objective for removing the material from the mummified remains. The endoscopist should record what analyses are to be conducted on the material and to which laboratory the material will likely be sent. If the laboratory selection changes, notation should be made on the record. The second page of the form also provides space to detail any special procedures or modifications to instrumentation made during the course of the study. Data entered into this section of the form allow the researcher to document novel approaches employed, the results of those approaches, and to suggest future research directions related to any special applications. Finally, a section is provided for the researcher to comment on the overall procedure, its findings, and efficacy. The researcher is encouraged to reflect on the procedures conducted and suggest remedies to any problems that may have arisen. Additionally, the researcher may want to comment on a novel approach to the varied aspects of the procedure. If data are collected and reported in a uniform fashion, future researchers will be better able to reproduce those procedures and create new ideas about procedural problems or challenges encountered. In addition, the form encourages standardization of the endoscopic procedure by ensuring that radiography, anatomical sketching, and photography are all included as critical aspects of the endoscopy application in anthropological and archaeological research.

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Procedural Standards for Endoscopic Paleoimaging in Anthropological and Archaeological Research If endoscopy is to reach its full potential as a tool for data collection in anthropological and archaeological research, researchers must continue to explore its application possibilities. If the application of endoscopic methods is limited to the medical approach of target-focused biopsy procedures, the full contribution of endoscopic application will not be realized. With the advancement of the application of this technology as the base construct, we recommend a more global approach. We recommend the following procedural framework as a methodological standard for endoscopy application in anthropological