This book, now in its third edition, aims to promote a deeper understanding of the scientific and clinical basis of nuclear medicine and the new directions in medical imaging. The new edition has been revised and updated to reflect recent changes and to ensure that the contents are in line with likely future directions. The book starts by providing essential information on general pathophysiology, cell structure and cell biology as well as the mechanisms of radiopharmaceutical localization in different tissues and cells. The clinical applications of nuclear medicine are then presented in a series of chapters that cover every major organ system and relate the basic knowledge of anatomy, physiology and pathology to the clinical utilization of various scintigraphic modalities. The therapeutic applications of nuclear medicine are discussed in a separate chapter, and the final chapter is devoted to the biologic effects of ionizing radiations, including radiation from medical procedures.