The Information Processing in Medical Imaging Conference is a biennial conference, held alternatively in Europe and in the United States of America. The subject of the conference is the use of computers and mathematics in medical imaging, the evaluation of new imaging techniques, image processing, image analysis, diagnostic decision making and related fields. The conference brings together the top specialists in the field (both scientists and medical doctors) and other participants doing active research on the subject of the conference. The success of a meeting primarily depends on the enthusiasm of the participants. It also greatly depends on the financial support as well as on the personal efforts of the technical staff and collaborators of the organizers. To all who made this conference a success, the members of the organizing committee want to express their sineere thanks. In particular, the organizers want to acknowledge the help received from: De Vice-Voorzitter van de Vlaamse Executieve De Minister van Onderwijs Het Nationaal Fonds voor Wetenschappelijk Onderzoek De Vrije Universiteit Brussel Adac Agfa-Gevaert Bruker Spectrospin Byk Belga Elseint Instituut voor Radioelementen, IRE Nucleobel Solco Sonotron VII TABLE OF CONTENTS Foreword. v A. VENOT, J.L. GOLMARD, J.F. LEBRUCHEC, L. PRONZATO, E. WALTER, G. FRIJA and J.C. ROUCAYROL: "Digital Methods for Change Detection in Medical lmages."

Throughout the twentieth century, interest in sport has evidenced a major increase worldwide and a new field of sports medicine has emerged. Sport spectators hip has been stimulated in part by the increased ease of international travel and the intro duction of new means of communication. Interest in professional sports and in such events as the World Cup and the Olympic Garnes has never been higher and the general popularity of sports has drawn increasingly greater numbers of young people to sports participation. Interest in sports participation has been strength ened both by the provision of numerous sports facilities to populations throughout the world and the accumulating information base that relates regular participation in programs of sport and exercise to health enhancement. Along with in creases in interest and participation has corne a need for a better understanding of the physiological changes accompanying muscular activity and of the trauma that can result from both competitive sport and recreational exercise.

We are in the midst of major advances in medical imaging, converting static pre sentation of anatomic information into near real-time interactive imaging and displays capable of depicting both structure and function. This will have pro found impact on diagnosis and image-guided therapies. These advances have been most notable in the modalities of computed tomog raphy and magnetic resonance. These technologies have become capable of ac quiring volumetric images in short periods of time. Speed gains in MRI were very significant in the early 1990s with the development of clinically usable pulse se quences for gradient-recalled and echo-planar imaging. It appears that further speed gains in MRI will be difficult to achieve. The development of spiral CT has ushered in an era in which major speed gains in CT are also possible. This has enabled creation of new types of applica tions such as CT angiography, which has already come to replace catheter angio graphy at many medical centers throughout the world. We are very pleased that the results from industrial and academic laboratories have been transferred to the bedside to improve patient care at a speed that may be faster than in any other area of medicine. Concurrent with advances in CT technology there have been dramatic strides in the performance characteristics and costs of computer hardware and software.

This book deals with all aspects of surgery of the pancreas. The leading authorities from all over the world have contributed to this volume. Surgery of acute pancreatitis, chronic pancreatitis and pancreatic malignancies is demonstrated. This book defines standards for pancreaticand general surgeons. In addition all aspects of diagnostics, pathophysiology and basic scientific data with regard to pancreatic disease are presented.

Over the past few years, a wealth of new insights have been gained and put to use in basic gastrointestinal tumor research, including tumor suppressor genes, oncogenes, cell-cycle con- trol, apoptosis, adhesion receptors, signal transduction, and gene therapy. Similarly, progress has been made in preven- tion, molecular diagnosis, laparoscopic staging, and antibody- based immunotherapy, and new drugs such as thyrnidylate and topoisomerase I inhibitors have been developed espe- cially for the treatment of colorectal carcinoma. Despite this burgeoning of knowledge in both basic and clinical research, however, we have just begun to put these results into clinical practice. Therefore, the key goal of this volume is to bring together basic and clinical research findings so as to facilitate the translation of these advances into the clinical manage- ment of gastrointestinal tumors. We hope that this volume, which covers a broad spectrum of research and clinical medicine, will impart new insights and greater understanding to all those interested in the therapy of gastrointestinal tumors and will stimulate further scientific research. Berlin, January 1996 E. D. Kreuser P. M. Schlag Contents 1 I. Basic Research S. J. Meltzer The Molecular Biology of Esophageal Carcinoma 1 E. R. Greenberg Preventing Colorectal Cancer...9 M. Streit, R. Schmidt, R. U. Hi/genfeld, E. Thiel, and E. -D. Kreuser Adhesion Receptors in Malignant Transformation and Dissemination of Gastrointestinal Tumors...19 R. Kaiser, E. Thiel, and E. -D. Kreuser Human Gene Therapy in Gastrointestinal Diseases: In Vivo and In Vitro Approaches ...

When I planned this book seven years ago I had my graduate students at the University of Ulm in mind, diploma as well as doctoral students, who often asked me what literature they should work with. I used to suggest a list of ten to twenty (for my taste: excellent) treatises on NMR. Apparently this did not make them entirely happy. The difficulty which newcomers to the field face is to practise and to apply theoretical formalisms from different sources while still learning the principles of NMR and being actively engaged in NMR research. Although the text presented here is largely based on my lecture notes, the result is a "working book" rather than an introduction. It is intended to provide direct access to the basic information one needs for NMR diffusometry, relaxometry, and tomography applications. A "working book" is certainly not suitable to be read starting on page one and then carrying on until the last page. Boldly extrapolating my own reading habits to those of the typical scientist I am sure that this is not the way in which monographs of this kind are read nowadays. So my aim was to produce a treatise that offers easy and quick access for the reader to relevant matters of interest. I tried hard to ease the comprehension of NMR principles by extensive cross-referencing among the sections and chapters. Tomography, diffusometry and relaxometry are fields based on common phys ical principles."

The imaging aspects of radiography have undergone con many sources and was in general freely given when requested siderable change in the last few years and as a teacher of and this is gratefully acknowledged. In particular I would radiography for many years I have often noticed the lack of a like to express my sincere thanks for help and information to comprehensive reference book for students. This book is an Mr J. Day of DuPont (UK) Ltd. particularly for the infor attempt to correct that situation and I hope this text will be mation and illustrations in the chapter on automated film of value not only to student radiographers but also prac handling; Mr D. Harper and Mr R. Black of Kodak Ltd. ; tising radiographers as well. Fujimex Ltd. ; CEA of Sweden; 3M (UK) Ltd. ; Wardray Much of the information is based on personal experiment Products Ltd. ; D. A. Pitman Ltd. ; Agfa-Gevaert; PSR Ltd. and the knowledge gained of students' difficulties in studying for their help with information on silver recovery, and this subject. I have attempted to gather together in one book Radiatron Ltd. for their help with safelighting. All were most all the information required to understand the fundamentals helpful in my many requests for information. of the subject both for examination and for practice. Some To Mrs A. Dalton and Mrs P.

In Videofluorscopic Studies of Speech in Patients with Cleft Palate, Drs. M.L. Skolnick and E.R. Cohn present multiview videofluoroscopy as a technique for the radiological evaluation of speech defects in patients with cleft palate. Dr. Skolnick's invaluable contributions as both the originator and leading authority on the subject are discussed in a concise, clinical fashion. Topics examined include the anatomy and imaging of the velopharyngeal portal; the equipment and techniques of multiview videofluoroscopy; the interpretation of results and various patterns of velopharyngeal closure; Passavant's Ridge and patterns of velopharyngeal closure; normal and abnormal speech production; and the evaluation of test results. This book is the only source which concisely and completely describes the technique and its interpretations for those who need a description of the clinical procedure.

The visualization of human anatomy for diagnostic, therapeutic, and educational pur poses has long been a challenge for scientists and artists. In vivo medical imaging could not be introduced until the discovery of X-rays by Wilhelm Conrad ROntgen in 1895. With the early medical imaging techniques which are still in use today, the three-dimensional reality of the human body can only be visualized in two-dimensional projections or cross-sections. Recently, biomedical engineering and computer science have begun to offer the potential of producing natural three-dimensional views of the human anatomy of living subjects. For a broad application of such technology, many scientific and engineering problems still have to be solved. In order to stimulate progress, the NATO Advanced Research Workshop in Travemiinde, West Germany, from June 25 to 29 was organized. It brought together approximately 50 experts in 3D-medical imaging from allover the world. Among the list of topics image acquisition was addressed first, since its quality decisively influences the quality of the 3D-images. For 3D-image generation - in distinction to 2D imaging - a decision has to be made as to which objects contained in the data set are to be visualized. Therefore special emphasis was laid on methods of object definition. For the final visualization of the segmented objects a large variety of visualization algorithms have been proposed in the past. The meeting assessed these techniques.

2 Diagnostic Use of Radiographic Methods in Coronary Disease. . . . . . . . . . . . . . . . . . . . . . . . . . 56 3 Material. . . . . . . . . . . . . . . . . . . . . . . . . 58 4 Mode of Operation . . . . . . . . . . . . . 62 5 Radiological Projections. . . . . . . . . . . . . . . . . 63 6 Monitoring of Cardiac Parameters . . . . . . . . . . . . 64 7 Pharmacological Tests . . . . . . . . . . . . . . . . 66 7. 1 Coronary Arteries . . . . . . . . . . . . . . . . . . . . . 66 7. 2 Left Ventricle. . . . . . . . . . . . . . . . . . . . . . . . 67 8 Accidents and Risks of Coronary Arteriography . . . . . 67 References . . . . . . . . . . . . . . . . . . . . . . . . . 68 III Angiographic Explorations: Normal Results . . . 71 1 Left Ventricle and Left Ventricular Function 71 1. 1 Radiological Anatomy. . . . . . . . . . . . 71 1. 2 Normal Kinetics. . . . . . . . . . . . . . . 77 1. 3 Analysis of Wall Contraction . . . . . . 78 1. 4 Volumes and Function Indexes. . . . . . . 81 2 Coronary Arteries and Veins . . . . . . . . 84 2. 1 Origin, Calibre and Preponderance of the Coronary Arteries . . . . . . . . . . . . . . . . . . . . . . . . 84 2. 2 Nomenclature and Segmentation of the Coronary Arteries . . . . . . . . . . . . . . . . . . . . . . 87 2. 3 A Reminder About the Physiology of Coronary Circulation . . . . . . . . . . . 93 2. 4 Angiographic Anatomy . . . . . . . . . . 94 2. 4. 1 Left Coronary Artery . . . . . . . . . . . 94 2. 4. 2 Right Coronary Artery. . . . . . . . . . . . . 95 2. 4. 3 Vascularization of Nodes and the Conduction System . . 96 2. 4. 4 Interconnecting Anastomoses . . . . . . . . . . . . . . . 97 2. 5 Coronary Veins . . . . . . . . . . . . . . . . . . . 97 References . . . . . . . . . . . . . . . . . . . . . . . . . 98 IV Angiographic Explorations: Congenital Anomalies of the Coronary Arteries. . . . . . . . . . . . . . . . . . . . . . . . 100 1 Anomalies of the Origin, Course and Distribution of Coronary Arteries Arising from the Aorta . . . . . . . . 100 2 Abnormal Origin of a Coronary Artery from the Pulmonary Artery . . . . . . . . . . . . . . . . . . . . . 101 3 Anomalies in the Diameter of Coronary Arteries . . . . . 104 4 Coronary Fistulae . . . . . . . . . . . 109 References . . . . . . . . . . . . . . . . . . . . . . . . . 113 VII V Angiographic Explorations: Coronary Atheroma. . . . . . . . 114 1 Left Ventricle . . . . . . . . . . . . . . . . . . . . . . . . 114 1. 1 Morphological Anomalies: Bulging and Lacuna-Like Aspects . . . . . . . . . . . . . . . . . . . . . . . . . . .

This book is not intended as a general text on MRI. It is written as an intro duction to the field, for nonexperts. We present here a simple exposition of certain aspects of MRI that are important to understand to use this valuable diagnostic tool intelligently in a clinical setting. The basic principles are presented nonmathematically, using no equations and a minimum of symbols and abbreviations. For those requiring a deeper understanding of MRI, this book will help facilitate the transition to standard texts. Chapters 1 through 4 provide a general introduction to the phenomenon of nuclear magnetic resonance and how it is used in imaging. Chapter 1 discus ses magnetic resonance, using a compass needle as an example. In Chapter 2, the transition to the magnetic resonance of the atomic nucleus is made. Chapter 3 describes the principles of imaging. In Chapter 4, the terms T 1 and T 2 are described and their relationship to tissue characterization; the fun damental role of thermal magnetic noise in T 1 and T 2 is discussed.

An Advanced Study Institute on Ultrasonics in Medical Diagnosis was held in Milan, Italy, from 10 to 15 June 1974. This ASI was of a short five-day duration and limited to cardiac diagnosis by ultra sound only. Since that time, the field of diagnostic imaging in medicine has literally exploded with new and improved means of medical diagnosis such as computed tomography, microwaves, nuclear magnetic resonance and other sophisticated techniques. These developments have enabled medical practitioners to make diagnoses with a minimum of danger to the patient, and a maximum of accuracy never before possible, and represent a multi-quantum advance over the early state-of-the-art presented at the 1974 ASI. Since then, several meetings have taken place on these individual topics to bring together experts who presented their latest research results, but none have discussed the entire field of diagnostic imaging in medicine in one meeting nor have they had the teaching character of an Advanced Study Institute. The art and science of medicine have been altered repeatedly during the eight year interval since the last ASI. Today's clinician must be part technologist and must be enough of an investigator to understand and appreciate the scientific method. The current complex advances in instrumentation and pharmacology have had a marked effect on how medicine is practiced. There was, therefore, an urgent need to bring the entire field of imaging in medicine to one teaching podium where the many advances of the last six or seven years could be reviewed.

This book is intended as a short guide to the visualization of the anatomy of the normal brain by means of the NMR tomogram. The first section comprises a brief introduction to the physical and technical aspects of NMR. This is followed by the atlas section, which pursues a number of objectives. On the basis of two important NMR imaging techniques, the spin-echo technique and the inversion-recovery technique, those experi enced in CT are given the opportunity to familiarize themselves with the differences in tissue contrast that exist in NMR scans despite their appar ent similarity to conventional CT scans. The mode of action of the two NMR imaging techniques is explained in the technical introduction. An additional innovation is the possibility of producing sections that are not, as in CT scanning, limited by the body of the patient. The sagittal and frontal sections parallel to the plane of the face can show an unfamiliar, but particularly clear, image of the anatomy of the head and brain com pared with conventional horizontal sections. An anatomical description accompanying every section is provided by way of clarification. A particular advantage of NMR imaging, namely, the absence of ionizing radiation and, thus, an injurious effect on biological systems (Budinger 1981), makes it possible to provide a systematic visualization of a healthy human brain in a living person in three planes, arranged at right angles to one another."

The quantitative analysis of blood flow within central and peripheral blood vessels has attracted more and more interest, for with the rapid developments in vascular surgery and the introduction of percutaneous transluminal angioplasty, it is becom ing increasingly important to be able to measure regional blood flow in man. In clinical radiology, angiography has been used predominantly from the point of view of its morphological applications. However, theoretically angiography may also be regarded as a specific application of indicator-dilution measurements of blood flow. The indicator is contrast medium (CM), the changing concentration of which is re corded by cinematography or video-electronic systems at sites downstream from the point of injection. The curves of density thus obtained correspond to indicator-di lution curves. The blood flow can be calculated from the concentration-time curves ofCM in much the same way as it is estimated from other indicator-dilution curves. In our early work with clinical application of videodensitometric measurement of blood flow in the iliac artery, we found that this method did not offer as high a degree of accuracy as one would have expected from investigations by other authors. We saw that we needed to examine the following problems: 1. We had to investigate whether our conventional X-ray equipment and video densitometer could be viewed as a linear measuring system. To what extent do unavoidable nonlinear changes in the measuring signals influence the blood flow values? 2."

One of the first applications of ultrasound was in submarine sonar equip ment. Since then ultrasound has found increasing applications, particularly in industry, but increasingly in biomedicine. For many years ultrasound has been used in physical therapy, although only in the past decade or two has it evolved from laboratory curiosity to a well-established diagnostic imaging modality. Ultrasound is now a widely accepted, indeed pervasive, diagnos tic and therapeutic tool in the medical field, and its applications are increasing rapidly. Our intent in developing this book is to provide a coherent tutorial intro duction to the field of medical ultrasound at a level suitable for those en tering the area from either medical or scientific backgrounds. The topics discussed should be of interest to nearly all medical and health care per sonnel needing to understand or operate ultrasonic devices, including clini cians, medical technicians, physiotherapists, medical physicists, and other biomedical scientists interested in the field. The book opens with a description of the basic principles of propagating acoustic waves, explains how they interact with a wide range of biological systems, and outlines the effects they produce. To provide practical infor mation to operators of ultrasound equipment, we have included thorough coverage of the details of ultrasonic instrumentation and measurement techniques, and set forth the framework for an effective quality assurance program."

During the past few years, a considerable number of monographs on bone tumors have been published. They are mainly restricted to bone tumors as clinical-pathological entities, since their diagnosis, more than that of other tumors, requires the interdisciplinary cooperation between orthopedic specialist, radiologist, and pathologist. However, investiga tions concerning the histogenesis of bone tumors are rather limited, although they might be helpful in explaining the unique morphological heterogeneity of tumors of the skeletal system. Furthermore, the histo genetic approach in the study of bone tumors may facilitate the inter pretation of the advanced cytobiological methods available for improv ing classification and diagnosis. Therefore, this volume presents recent pathological advances in the biological characterization of bone tumors. A major chapter deals with the differential diagnosis of Ewing's sarcoma as regards its demarcation from the so-called neuroectodermal tumor of bone. The analysis of the ground substances in bone-forming tumors may be helpful for their classification. Therefore the volume includes a chapter on the biochemical and histochemical analysis of different osteosarcoma types. Recently it has become clear that in addition to different collagen types which are not specific for bone tissue, several bone-specific proteins occur, one of which is osteonectin. Its distribu tion is obviously important for the classification and diagnosis of osteo blastic tumors. Proliferative behavior is of major importance for the diagnosis of malignant tumors.

It is a great pleasure for me to introduce and to recommend this much needed text on double contrast examination of the colon. It is aimed both at clinicians who request X-ray examinations of the colon and at radiologists who must per form and interpret these studies. Over the past decade there has been renewed interest in X-ray examination of the colon despite the tremendous advances in endoscopy and imaging tech nology. This renewed interest is evidenced by the proliferation of new books on radiology of the colon. However, previous discussions of double contrast ex amination have concentrated primarily on the technique with too little attention to the understanding and interpretation of the radiologic images. This volume is unique in its emphasis on the basics of image formation and interpretation. It emphasizes the importance of the anteroposterior relation ships of the colon in determining the distribution of barium and air. It also rec ognizes the influence oflocation on the radiologic appearance of the lesion. The authors demonstrate a profound understanding of the principles of double contrast diagnosis as applied to the colon. They also have a good grasp of the gross pathologic changes underlying the radiologic images. The material is presented in a logical and analytical method which should be particularly useful to the beginner in this field. There are many helpful diagrams and the ra diographic illustrations are of excellent quality."

In January 1995, 300 participants from Asia, USA, and Europe lively discussed the "State of the Art and Future Aspects of CT" in Peking, China. The workshop was designed to cover all essential aspects of modern CT imaging including the historical development, different techniques, contrast agents, organ systems, and indications. The comparative evaluation of CT versus MRI and ultrasound was a central topic. Additionally, a special session was dedicated to "Angiography Tomorrow." This book summarizes the state of the art in both conventional and spiral CT imaging and provides some suggestions as for the future role of the method.

Trauma to the abdomen, both accidental and willful, has become increasingly common in this era of increasing violence. Large numbers of patients all over the country are admitted to emergency rooms because of abdominal trauma of varying degrees of severity. All too often the correct diagnosis is suspected belatedly or not at all, so that proper treatment is not initiated in sufficient time to be lifesaving. Not infre quently, the injured patient is examined by an intern or an insufficiently experienced resident physician. Even in instances where more senior internists and surgeons are available, detailed knowledge about the necessary methodology to establish the correct diagnosis and institute the appropriate treatment is lacking. This monograph, representing the felicitous collaboration of a surgeon and a radiolo gist together with several other contributors, is timely and important. The authors (and their contributors) have approached their subject with a wealth of clinical experi ence obtained in several very active acute-care municipal hospitals in the largest city in this country. They have observed and treated a very large number of patients with a multitude of traumatic causes, including firearm injuries, stab wounds, vehicular accidents, falls, and assaults. The authors have divided this work into four main sections: General Perspectives on Abdominal Injury, Types of Abdominal Injuries, Specific Diagnostic Techniques, and Specific Organ or Supporting-Structure Injury."

This atlas is a selection of roentgenograms of patients who visited the radiology departments at the University Hospital in Leiden between 1970 and 1978, the Free University Hospital in Amsterdam in 1979, and the radiology department at the Indiana University Medical School in Indianapolis in 1977. The most common radiological abnormalities of the small intestine are illustrated clearly, unhindered by flocculation or segmentation of the contrast fluid. The authors believe this book is a definite contribution to the goal of precise early small bowel diagnosis. However, the key to good diagnosis is not only a superb examination technique, but also the knowledge, the character, and the personal perfectionism of the physician. If these factors are optimal, then the best possible roentgenographic series will be obtained - at least as far as the technique is concerned. All patients illustrated here were examined by using the enteroclysis technique. With this method of small bowel examination, the contrast fluid is administered via an infusion directly into the duodenum instead of orally. The infusion method has added a new dimension to the usual radiological examination of the small intestine. This method is also especially suited for the comparative evaluation of motility, and the study of disturbed motility. Throughout the course of the examination, the technique can be adapted to special situations at any given moment and can be modified to produce precise diagnostic roentgenograms and diagnosis.

This book is not meant to be a textbook or a handbook of phlebography of the lower limbs. It is an atlas aimed only at teaching one how to read an interpret phlebograms, and is of considerable importance as it represents the standard investigatory method used to check the reliability of other diagnostic methods concerning venous circulation. Regarding diagnosis, nothing is more certain than the phlebographic demonstration of a thrombus; moreover, even if the thrombus is not demonstrable, as in certain phlebites. it is still possible to establish the diagnosis with adequate knowledge of the radio anatomy of the non-opacified veins and the demonstration of marked collateral circulation. Therefore this investigation must be carried out very carefully with particular attention to interpretation. The technique was first used in man in 1923 and is now employed world wide; better tolerated contrast materials render it almost innocuous; the occurrence of very few incidences of non-tolerance does not diminish the value of this method. We have purposely reduced the text to legends of the illustration and withheld the bibliography in so far as it is meant to be a teaching program by way of pictures without any reference to past or present publications.

J.J. Broerse, Radiobiological Institute TNO, Rijswijk, The Netherlands, and T .J. MacVittie, Armed Forces Radiobiology Research Institute, Bethesda, MD, USA. During the past decade, relatively few new studies have been initiated on the response of different species to high-dose, total-body irradia- tion. For information on the LDSO/30d (the dose which produces 50 percent lethality within 30 days), one is generally referred to the older literature (e. g., Bond, Fliedner and Archambeau, 1965). Compari- son of experimental data reveals considerable variations in LDSD values even after total-body irradiation with conventional X rays, ranging from 4 to 6 Gy in the monkey, 7.1 to 9 Gy in the rat and from 6.4 to 9 Gy in the mouse (see also Hall, 1978). Part of the discrepancy in the LDso values can possibly be attributed to inadequacies in the dosimetry procedures and exposure arrangements employed. As far as clinical experience is concerned, there is now an appreciable amount of information available about the effect of total- body irradiation as a conditioning treatment for bone marrow transplan- tation in patients suffering from leukaemia or aplastic anaemia. The results from different centres, including the incidence of complications such as radiation pneumonitis, are considerably different. This can part I y be connected with the application of different radiation sched- ules: large single dose versus fractionated or protracted irradiation.

As an addition to the European postgraduate training system for young neurosurgeons we began to publish in 1974 this series devoted to Advances and Technical Standards in Neurosurgery which was later sponsored by the European Association of Neurosurgical Societies. The fact that the English language is well on the way to becoming the international medium at European scientific conferences is a great asset in terms of mutual understanding. Therefore we have decided to publish all contributions in English, regardless of the native language of the authors. All contributions are submitted to the entire editorial board before publication of any volume. Our series is not intended to compete with the publications of original scientific papers in other neurosurgical journals. Our intention is, rather, to present fields of neurosurgery and related areas in which important recent advances have been made. The contributions are written by specialists in the given fields and constitute the first part of each volume. In the second part of each volume, we publish detailed descriptions Of standard operative procedures, furnished by experienced clinicians; in these articles the authors describe the techniques they employ and explain the advantages, difficulties and risks involved in the various procedures. This part is intended primarily to assist young neurosurgeons in their post graduate training. However, we are convinced that it will also be useful to experienced, fully trained neurosurgeons."

Proceedings of the 9th Conference, Washington D.C., 10-14 June 1985 Sponsored by the Clinical Center and the Fogarty International Center of the National Institutes of Health, Bethesda, Maryland, USA

7 Les Houches The purpose of this workshop was to bring together, for the first time, active scientists from very different fields, such as physics, chemistry, physiology and the behavioural sciences, all having a common interest: The interac tion of static magnetic fields with biological and macromolecular matter. As physicists, biologists and medical scientists naturally have different scientific competences, attitudes and abilities, this appeared to be an enterprise of un certain issue. However, it turned out that all participants tried to find (and many succeeded in reaching) a mutual basis of understanding. Thanks to a fair number of outstanding, comprehensive talks and to very active discus sions, most of us, we believe, have substantially enlarged our insight into the actual hard facts within a research area that was considered for a long time - and still remains in many aspects - somewhat controversial. The perhaps most striking and useful reaction to magnetic fields at the supermolecular level is the alignment of biopolymers, proteins, viruses, large assemblies such as retinal rods and membranes when suspended in a solvent, usually water. The ease of alignment depends on the anisotropy of the dia magnetic susceptibility of the constituent groups and bonds and, in addition, on the extent of their mutual orientational order inside a macromolecular assembly. Here very strong fields above I-lOT appear to be necessary, in general, to achieve measurable alignment."