New developments in the application of radiation to medicine are occurring so rapidly that this is possibly the fastest growing branch of medicine today. In the past decade alone, we have seen enormous progress made in tech­ niques used both for the diagnosis of disease, such as computerized tomography, digital radiography, ultrasonography, computerized nuclear medicine scanning, and nuclear magnetic resonance imaging, and for its treatment, such as the radiotherapeutic utilization of high-LET radiations, and the widespread application of computers to perform elegant dosimetry calculations for 3-D treatment planning and imaging. This series will provide in-depth reviews of the many spectacular technical advances and sophisticated concepts, which