[Basis of radiotherapy for improved tumor control and preservation of normal function]

Historical overview of development of radiotherapy, its biological basis and radiation sources since the discovery of x-ray are presented. The present status and problems as well as future direction of radiation oncology studies such as clinical cyclotron for heavy ions, predictive assays and indicators, and various fractionation schemes are discussed. Better understanding of the current status and problems of various disciplines by each specialist is important for the improvement of combination treatment using different modalities. Also, better understanding of radiotherapy by other specialists and cooperation with each other are the key to the development of rather weak radiation oncology programs in the Japanese medical system.