40 years of radiobiology: its impact on radiotherapy. (Eighteenth Douglas Lea Lecture)

The contributions of radiobiology to radiotherapy in the past 40 years are reviewed, taking the work of Gray and Read on bean roots with high LET radiation as the starting point. The main impact has been strategic and didactic because methods of measuring parameters in patients so as to affect individual treatments have not yet been developed. Many patients are now being treated with radiotherapy who would have been considered unsuitable 40 years ago and the radiobiological reasons for these changes are discussed. Improvements that have occurred in radiotherapy are reviewed and some projections about future potential improvements are made.