The most frequently requested investigation in any nuclear medicine department remains the technetium-99m (99mTc)-labelled diphosphonate bone scan. Despite rapid advances in all imaging modalities. there has been no serious challenge to the role of bone scanning in the evaluation of the skeleton. The main reason for this is the exquisite sensitivity of the bone scan for lesion detection. combined with clear visualisation of the whole skeleton. In recent years several new diphosphonate agents have become available with claims for superior imaging of the skeleton. Essentially. they all have higher affinity for bone. thus allowing the normal skeleton to be visualised all the more clearly. However. as will be dis cussed. this may occur at some cost to the principal role of bone scanning. lesion detection. The major strength of nuclear medicine is its ability to provide functional and physiological information. With bone scanning this leads to high sensitivity for focal disease if there has been any disturbance of skeletal metabolism. However. in many other clinical situations. and particularly in metabolic bone disease. more generalised alteration in skeletal turnover may occur. and quantitation of diphosphonate uptake by the skeleton can provide valuable clinical information."

Safety and Efficacy of Radiopharmaceuticals was established as a very important and comprehensive subject at the First Europe an Symposium on Radiopharmacy and Radiopharmaceuticals in Denmark in 1983. The interest in this subject has grown considerably since then due to the growing interest among national authorities to deal with radiopharmaceuticals. The introduction in recent years of nuclear medicine techniques based on radioactive labelled cells and on monoclonal antibodies has stressed the importance of a well functioning approval system for the clinical trial and use of new radiopharmaceuticals. The process of transferring the experience from the non radioactive drug field into the area of radiopharmaceuticals is still ongoing. International organisations such as the World Health Organisa tion is also including this into their quality assurance programme from both the radiopharmaceutical and the radiation hygiene point of view. In order to give an up-to date survey of these areas, experts were invited to prepare review papers under the following headings: Safety and Efficacy of Radiophar maceuticals with Emphasis on Biological Products, Radiophar macy/Radiation Hygiene, Legal Aspects of the Introduction of New Radiopharmaceuticals and some selected aspects of Good Radiopharmacy Practice."

In the field of Hodgkin's lymphoma, many new data have been collected during the last decade both on the cell of origin of this disease and on more effective therapies to cure the majority of pa tients even in the advanced stages. Therefore, it seems to be justi fied to compile these new data in a special volume of Recent Re sults in Cancer Research. This volume summarizes the contribu tions presented at the First International Symposium on Hodgkin's Disease that took place in Cologne (FRG) on October 2-3, 1988. There is little doubt that the Hodgkin and Reed-Sternberg (H and RS) cells and their variants represent the malignant population in Hodgkin's lymphoma; however, there is still a fierce debate as to the possible cell of origin of Hand RS cells. Many of the problems confounding earlier research into this question were related to the difficulty or virtual impossibility, of obtaining purified populations of Hand RS cells. Most of the recent progress stems from the establishment of permanent cell lines of Hand RS cells in culture.

The herpes group consists of viruses which have been placed together on the basis of a number of distinguishing features that they share in common (ANDRE WES, 1962). All these viruses are relatively large, possess identical morphological characteristics, contain DNA, and are extremely sensitive to inactivation by ether; these viruses are also assembled within the nucleus of the host cell and induce the formation of eosinophilic intranuclear inclusions. The epidemiology of some of the best known viruses in this group (herpes simplex, pseudorabies, and B-virus) is also similar (BURNET et aI., 1939). Herpes simplex virus exists in the latent state in man, the natural host for this virus, and becomes overt in individuals subject to some form of stress; this condition appears to be paralleled by pseudorabies virus in its natural host, swine and by B-virus in monkeys. In each instance, transmission of the virus to a susceptible host other than the natural one results usually in marked symptoms and death. This chapter is confined to a description of herpes simplex and pseudorabies viruses; B-virus is described separately elsewhere in the Hand book. Since the clinical aspects of the diseases caused by herpes simplex virus and pseudorabies virus have been well described, greater emphasis will be placed, therefore, on the basic biological and biochemical properties of these viruses; their clinical features will be discussed only briefly."

In dem Band XV /2 des Handbuches der medizinischen Radiologie wurden bei der klini- schen Nuklearmedizin bewuBt einige Kapitel herausgenommen, urn die weitere Entwicklung auf diesen Gebieten abzuwarten. Der vorliegende Band beinhaltet diese Kapitel. Die nuklear- medizinische Herz- und Kreislaufdiagnostik hat sich in der Zwischenzeit zu einem der drei wichtigsten diagnostischen Gebiete der Nuklearmedizin entwickelt. Dies nicht nur im Hin- blick auf die Aussagemoglichkeit sondern auch fur die Anzahl der zu untersuchenden Patien- ten. Mit dieser Entwicklung ist eindeutig bewiesen, daB die ExistenzHihigkeit der Nuklearme- dizin trotz erheblicher Leistungen anderer, auch bildgebenden Verfahren gewahrleistet ist. Die nuklearmedizinische Herz- und Kreislaufdiagnostik, die sich von den ersten Anfangen an, zunachst nur an einzelnen Zentren und hier auch langsam entwickelt hat, ist in ihrer Bedeutung in den letzten lahren sprunghaft angestiegen. Hinzu kommt allerdings, daB das Untersuchungsverfahren innerhalb der nuklearmedizinischen Technik eines der schwierigsten und aufwendigsten ist und daB die Anforderungen an den Arzt im Hinblick auf seine diagno- stischen Aussagen eine groBe Erfahrung verlangen. Aus diesen Grunden ist der Thematik in dies em Band erheblicher Raum eingeraumt worden. Die einze1nen Kapitel demonstrieren die Entwicklung, die Effizienz und die diagnostischen Aussagemoglichkeiten. Gleiches gilt fur die nuklearmedizinischen Untersuchungsverfahren fur die Padiatrie. Durch die standige Verbesserung der Radiopharmaka und der MeBgerateeinheiten weitet sich dieses Gebiet mehr aus und bringt tatsachlich richtig in Anwendung gebracht erhebliche Fortschritte fUr die Differentialdiagnostik bei Erkrankungen im Sauglings- und Kindesalter.

th This book contains most of the papers presented at the Iy Inter- national Symposium on Bone Circulation which was held in Tou- louse, France, in September of1987. The symposium was attended by over 200 specialists from 17 different countries. Some of them were in Toulouse for the fourth time to discuss their favourite topic of study and research: bone circulation, its exploration, its pathol- ogy. Many, including a group of Japanese orthopaedic surgeons, were present for the first time, delighted to meet the authors of papers they had read. There were more than 100 oral presentations and posters, but many meaningful informal discussions took place both in and outside of the auditorium, in the hall and during meals. The organizers wished to maintain a balance between funda- mental themes and subjects of clinical and practical interest. This balance was accomplished: recent developments including scintig- raphy, magnetic resonance imaging and bone grafts played just as important a part as more sophisticated topics such as the evalua- tion of the blood flow rate in animal bone tissue. Thus, as did the previous symposia, this book aims to present a progress report on developments during the last 5 years in the study of bone circulation. We wish to thank all those who helped and encouraged us throughout the organization of the congress, especially C. Ar- noldi, M. Brookes, R. Burkhardt, L. Coutelier, S.P.F. Hughes, P. Kehr, J.P. Jones, A. Trias, K.Ono, T. Yizkelety and G.J.

Die Anfangszeit des Fachgebietes, welches wir heute mit Nuklearmedizin bezeichnen, konnen wir in die Jahre 1935, 1938 und 1940 zuriickverlegen. Wissenschaftler wie J.H. LAWRENCE, J.G. HAMILTON, G. HEVESY, S. HERTZ sollen hier stellvertretend fUr die groBe Anzah1 derer benannt werden, die in den ersten J ahren des Beginns einer rasanten Entwick1ung eines Fachgebietes erfo1greich tiitig waren. Die Anwendung von offenen, kiinstlichen Radionuk1iden in der Forschung, der klinischen Diagnostik und der Therapie hat eine Basis, die auf drei Siiu1en ruht, niim1ich Radiophar- maka, Geriitetechnik und Strah1enschutz. Dieses Grund1ageninstrumentarium der Nu- k1earmedizin ist in diesem ersten Tei1 der Nuk1earmedizin des Handbuches der Medizini- schen Radio1ogie abgehande1t. Ein zweiter Tei1 befaBt sich mit der Diagnostik, Therapie und klinischen Forschung (Handbuch der Medizinischen Radio1ogie, Band XV /2). Verg1eicht man die Entwick1ung des Fachgebietes Nuk1earmedizin mit anderen Fach- spezialitiiten, so ergibt sich eine Entwick1ung, die in kiirzester Zeit exp1osionsartig, sowoh1 von dem Instrumentarium, d.h. den Radiopharmazeutika und der Geriitetechnik aus, a1s auch in bezug auf die k1inische Anwendung erheb1iche Fortschritte aufweist. Diese sind so, daB sich bei der Erarbeitung der ersten beiden Biinde der Nuk1earmedizin innerha1b dieser Handbuchreihe deut1ich die Notwendigkeit weiterer Tei1e ergab, urn die Entwick1ungen, besonders auf dem Gebiet der Emissions-Computertomographie, des Ein- satzes von Zyk1otron produzierten kurz1ebigen Positronstrah1ern, der Datenverarbeitung und einiger sich rasch entwicke1nder klinischer Anwendungen abzuhandeln (Band XV f1 B und Band XV /3). Wichtig erscheint uns aber auch die Betrachtung iiber den Strah1enschutz und der Auswirkung der Strah1enschutzmaBnahmen und Gesetze in den einze1nen Liindern.

Basic research has thrown new light on the importance of free radicals in biol- ogy and medicine. The clarification of interactions opens numerous physio- logical and pathological processes to closer scrutiny. The pathophysiological processes are now understood, even though the basic mechanisms of free radi- cal reaction have as yet escaped full explanation. Asystematic approach makes it possible to re-evaluate and contrast the in- dications, reactions, and prospects for success. The extracellular significance of oxygen radicals in inflammatory condi- tions and their role in the destruction of bacteria in the phagosome of granu- locytes were primary factors intensifying research. Nature also provides a great number of examples which demonstrate that through the emergence of free radicals highly toxic combinations can form from innocuous substances. The reverse principle may also be encountered. Taking into account free radical reactions in pathomorphological investi- gations helps prepare the ground for causal therapy. Research into these phen- omena will contribute to a better understanding of physiological and patho- physiological processes. Many questions still remain unanswered, and it will take several years of research before the final stone is unturned.

PrHace Voici enfin l'Atlas de scintigraphie cardiaque, clair, demon- This Atlas 0/ cardiac scintigraphy - clearly presented and stratif, comprehensible et que nous attendions tous, car- easy to understand - has long been awaited by all clinical diologues c1iniciens. cardiologists. Il n'etait certainement pas necessaire d'etre grand clerc At the time when the first hesitating steps were being taken pour prevoir, lors des premiers balbutiements de cette in this field, one did not have to be an expert to foresee methode, la rapide importance qu'elle prendrait; beau- how important these tests would soon become. It was coup plus difficile etait, sans nul doute, de penetrer dans ce without doubt more difficult to penetrate into the select cenacle de physiciens, de les suivre, meme de loin, dans le world ofthis group ofphysicians, to follow, evenfrom a long cheminement de leurs travaux, de participer active- distance, the progress oftheir work, to play an active part ment aleurs progres, d'avoir meme une comprehension in their etIorts or to understand clearly their initial results claire de leurs premiers resultats: quelle etrange represen- represented by this strange, blurred, vague and poorly sys- tation en etIet, floue, indecise, mal systematisee, des ditIe- tematised image ofthe ditIerent areas ofuptake and of car- rents niveaux de fixation et de la topographie cardiaque. diac anatomy.

Congenital hip dysplasia and dislocation are common diseases of newborns and small infants, with frequently severe consequences if orthopaedic therapy is not initiated at an early stage. Therefore many clinicians have been looking for a simple method for the investigation of the hip joint in the early neonatal period. Up to 1980 the diagnosis of hip dysplasia could usually not be made before the 3rd month of life, by means of pelvic roentgenography. Only incomplete or complete unilateral dislocations were diagnosed in the neonatal age group. In 1980, however, Graf, an Austrian orthopaedic surgeon, began using ultrasound investigation ofthe hip joint in newborns and small infants in order to make an early diagnosis and to avoid radiation exposure. The intention of the present study was to compare ultrasound of the hip joint with other established diagnostic procedures and to establish whether it is suitable as a screening procedure in newborns. 2 Incidence of Congenital Hip Dysplasia and Dislocation In 1972 Barlow reported that 90 % of hips which are unstable at birth develop to normal joints spontaneously without any therapy. Visser (1984) thus suggested determining the percentage of hip dislocations after the 2nd - 3rd month of life so that children with spontaneous stabilisation would be excluded.

Recent explorations in the neurosciences have been progressing towards an understanding of the relationship between brain struc ture and brain function. Having passed through an era which may be described as one of a localisationist philosophy, in which discrete brain areas were seen to subserve only discrete functions, the perspective of brain-behaviour relationships has advanced in recent years to an appreciation that a more holistic approach is not only heuristically valid, but is also most likely to lead to future advances. The close relationship between the mind and the brain has been appreciated since the time of Hippocrates when he opined 'men ought to know that from nothing else but thence [from the brain] comes joys, delights, laughter and sports, and sorrows, griefs, despondency and lamentations ... and by this same organ we become mad and delirious and fears and terrors assail us'. In the nineteenth century, particularly in France and Germany, descrip tions of what are now recognised to be independent neurological diseases emerged following empirical clinical observations. Investi gation led to the identification in many cases of underlying struc tural abnormalities which could be linked to pathological changes.

The ninth annual multidisciplinary symposium on clinical oncology organized by the Royal College of Radiologists was jointly arranged with the International Society for Radiation Oncology. It was held in London in February 1987 and discussed the biological and clinical basis of the effects of radiotherapy. Wherever possible lectures by an experimental scientist were paired with those of a clinical scientist in order to emphasize clinical relevance. It is hoped that this has resulted in a widely balanced view of the subject. The volume presents an updated version of these subjects based on those talks. After surgery, radiotherapy is the main treatment used in the management of patients with cancer. Its empirical success when first introduced is now backed up by a wealth of laboratory, clinical and experimental experience. New techniques for adminis tering the conventional X-ray therapy have been supplemented by methods which can be used to modify the radiation response. These include changes in dose rate or fractionation, and combined modality treatments including sensitization by drugs or heat. Other types of radiation, such as neutrons and other particles, are also now available which have enhanced physical and biological advantages.

A compilation of researchers' experience in the areas of bioanalysis, pharmacokinetics, and drug metabolism, to present an up-to-date and comprehensive treatise on the application of these and related technologies in drug discovery, development, and clinical use. Contents cover descriptions of analytical methods, in vitro metabolism technology and membrane transport, reappraisal of classical pharmacokinetic problems, and the time course of drug action. The book concludes with a description of PET and imaging methods in pharmacokinetics and an appendix containing a critical appraisal of computer methods and pharmacokinetic software available for PCs.

Pediatric Radiology texts typically provide only a cursory discussion of pediatric nuclear medicine techniques and applications while pediatric nuclear medicine texts typically review the so-called "structural imaging" modalities in only a superficial fashion. The standard texts do not adequately address the similarities and differences among different imaging modalities (X-rays, scintigraphy, ultrasonography, angiography, CT, MRI, etc.). The result is that the reader of these texts can not gain an understanding of the true role of nuclear medicine in pediatrics. With PEDIATRIC SKELETAL SCINTIGRAPHY, DRS. Connolly and Treves demonstrate the relative merits of scinitigraphy and other imaging tests in evaluating pediatric skeletal disorders. The emphasis is on situations where a complementary relationship exists between nuclear medicine and other modalities. In addition to showing cases in which scintigraphy is abnormal and structural imaging normal, the book also features cases where both scintigraphy and structural imaging are abnormal. The reader will gain an understanding of what can be gained from each modality, and when specific studies are indicated.

Neuroblastoma is the third most common malignancy of childhood. accounting for 8% of all cancers in patients under 15 years of age. In the majority of cases. by the time neuroblastoma is diagnosed. it has already spread from its site of origin to involve distant sites. Approximately 90% of cases of neuroblastoma can be diagnosed by a combination of techniques including detection of specific tumour markers in the urine. histopathological and immunocytological assessment of involved bone marrow and the 'characteristic' appearances of tumours dem- onstrated by computerised tomography and ultrasonography. However. despite this plethora of techniques. up to. 10% of cases of neuroblastoma are still difficult to diagnose and rely on excisional biopsy of a site of disease. It was against this background that the scintigraphic localisation of neuroblastoma with the radiolabelled guanethidine analogue. mIBG. became available. With mIBG scintigraphy it is now possible to demonstrate the presence of neuro- blastoma (and related tumours) at the primary site. soft tissue sites. in the bone marrow and in cortical bone. in a single investigation. The success of mIBG scintigraphy depends on many factors including the choice of isotope for labelling the mIBG. the equipment used to carry out the procedure. and the manipulation and interpretation of the information obtained. At the Royal Marsden Hospital we have performed over 100 mIBG studies in children. and our advice has frequently been sought by other centres who are. or intend to become.

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."

Selected Atlases of Gastrointestinal Scintigraphy is com- prised of five individual atlases in the reas of cholescintigraphy; gastrointestinal bleeding (RBC) scintigraphy; TC-99M labeled red blood cell liver scintigraphy; hepatic arterial perfusion scintigraphy and peritoneoscintigraphy.

The contents of this volume are based upon presentations made to the Second European Symposium on Radiopharmacy and Radiopharmaceuticals which was held in St. Catharine's College Cambridge in March 1985. This meeting was organized by the Radiopharmacy Group of the British Nuclear Medicine Society under the auspices of the European Joint Committee on Radio pharmaceuticals of the ENMS / SNME. The Joint Committee acknowledges the special effort which was made by the local organizers to prepare this meeting the quality of which is undoubtedly reflected in the proceedings. The wide ranging aspects of Radiopharmacy are reflected in this volume which not only deals with specialized topics, such as aerosols and biodistribution studies, but which also deals with the professional aspects of Radiopharmacy Practice. We are of the opinion that this book complements earlier publications to give an ongoing picture of the practice of Radiopharmacy and the state of the art in Europe. As well as acknowledging the contribution of the British Radiopharmacists I would also mention the support of my co chairman Prof. Dr M.G. Woldring, the members of the Joint Committee and last but not least Mrs. M. Busker, who prepared the camera ready copy. P.H. Cox Co-ordinating Chairman European Joint Committee on Radiopharmaceuticals Rotterdam XI CCNrRIBUTORS Anderson, M.L. - Pharnacy department, London Hospital London, UK. Angelberger, P. - Osterreichische Forschungszentrum Seibersdorf GmbH, Wien, Austria. Claessens, R.A.M.J. - Department of Nuclear Medicine, St. Radboud Ziekenhuis, Nijrnegen, The Netherlands."

MRI has opened up new possibilities in combined morphological and functional imaging, and now there is a book which discusses both aspects together. Two systems which already demonstrate the advantages of MRI are presented. In the cardiovascular system, motion and flow can be imaged so that even flow velocities in the deep vessels of the body can be measured, and turbulences can be identified. In the study of the kidneys, a combination of renally excreted contrast media and imaging provides within seconds insight into glomerular filtration in health and disease. These current possibilities, and their limitations, bring insight into the future potential of MRI.

This volume is based on a series of lectures delivered at a one-day teach ing symposium on functional and metabolic aspects of NMR measure ments held at the Middlesex Hospital Medical School on 1st September 1985 as a part of the European Nuclear Medicine Society Congress. Currently the major emphasis in medical NMR in vivo is on its poten tial to image and display abnormalities in conventional radiological im ages, providing increased contrast between normal and abnormal tissue, improved definition of vasculature, and possibly an increased potential for differential diagnosis. Although these areas are undeniably of major importance, it is probable that NMR will continue to complement con ventional measurement methods. The major potential benefits to be de rived from in vivo NMR measurements are likely to arise from its use as an instrument for functional and metabolic studies in both clinical re search and in the everyday management of patients. It is to this area that this volume is directed."

Advances in molecular biology describing important enzyme systems involved in drug conjugation and deconjugation reactions and recent work indicating the importance of drug and xenobiotic conjugates as transport forms of biologically active compounds are reviewed comprehensively. Part One describes molecular events associated with the expression and regulation of transferases and hydrolases involved in Phase II drug conjugation and deconjugation. Part Two deals with the regulation of Phase II conjugation, and Part Three reviews critically the importance of drug conjugates in pharmacology and toxicology. This volume is an up-to-date source of information on this topic and will be of broad interest to pharmacologists and toxicologists.

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.

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

The publication of this volume, which is based upon presentations made to the Third European Symposium on Radiopharmacology at Noordwijkerhout, April 22 - 24, 1982, is indicative of the continued interest in this sub-branch of Nuclear Medicine. The transactions of the first two meetings were published as Progress in Radiopharmacology, Volumes 1 and 2 by Elsevier/North-Holland Bio medical Press. We are particularly pleased to have reached an agreement with Martinus Nijhoff Publishers to include Progress in Radiopharmacology 3 in the series Developments in Nuclear Medicine. This not only ensures the continuity of the series but by including it in a series of Nuclear Medical Monographs the availability of the text to more general readers, for background information, is greatly enhanced. As with the previous two volumes each of the three topics has been so treated as to relate the biodistribution of the radiopharmaceuticals to normal and pathophysiological conditions to provide background information for the practising nuclear medical specialist. Special attention has been given to European activities but these have been clearly placed in context in relation to developments from outside Europe. The Third European Symposium on Radiopharmacology was held under the auspices of the European Joint Commitee on Radiopharmaceuticals of the European Nuclear Medicine Society and the Society of Nuclear Medicine Europe. Solco Nuclear, Basle, provided both financial and material support and I would like to thank Dr M. de Schrijver, Mr. I. Waser and Mrs. E. Rufenacht for their continued help and encouragement."

This book is based on a series of lectures given by an international team as part of a course on Bone Scintigraphy organized by the Boerhaave Committe for Postgraduate Medical Education (Leiden, January 1980). Bone scintigraphy and the use of radionuclide tracers in the investi gation of skeletal pathology has developed into a subject of its own. Significant advances in instrumentation, radiopharmaceuticals and data analysis has considerably widened the scope of clinical application. Beyond the important area of sensitive detection of malignant involve ment of the skeleton, major strides are being made in the investigation of benign bone disease and its metabolic aspects. The structure of this Boerhaave Course reflects this change, with considerable emphasis being given to the discussion of recent methods for tracer uptake quantitation, the discussion of inflammatory osseous disease, benign pathology in general and the investigation of metabolic bone disease. As a clinical tool, bone scintigraphy is present today in most if not all general and regional hospital institutions. It is a technique in demand by genera1 interns, surgeons, radiologists, paediatricians, oncologists and radiotherapists. New areas of application are being evaluated and to some extent consolidated. These include the difficult orthopaedic issues of bone avascularity, prosthesis loosening, infection and non-apparent fractures. A range of new techniques are available and applied to the follow-up of osteomalacia, osteoporosis, osteodystrophy and other con ditions where a more objective and even preferably a numerical approach is being explored."