Calculations for cancer radiotherapy with pion beams

It is stated that clinical trials with negative-pion beams for cancer radiotherapy will begin soon at four special facilities in the USA, Canada, and Switzerland. Negative pions are elementary particles which can be produced in high energy accelerators and which have properties that make them seem promising as a new way of treating tumours. The complex interactions that pions undergo in matter make it difficult to calculate dose patterns produced in a body irradiated by a pion beam and to solve that problem a unique combination of research in high energy physics and medicine is needed. Monte Carlo computer codes developed for radiation shielding and radiation protection studies have been adapted for use in dosimetry and treatment planning with negative pions. In this paper the properties of negative pions are compared with those of other types of radiation and some calculations are described that have been made to help assess the potential of negative pions for cancer radiotherapy. (author)