Type and energy spectra of secondaries from interactions of pions, and relevance to radiotherapy

Pions are probably the most complex radiation source used for radiotherapy. The energy deposition pattern in tissue, and hence the relative biological effectiveness, is dependent on type and energy spectra of the secondary particles produced by the capture of the pions. Not only the relative abundance of target nuclei, but also the chemical composition may be of importance in this respect. The available data and their relevance for the dosimetry and the therapy planning program developed at SIN (Swiss Institute for Nuclear Research) for dynamic treatment with pions are discussed. (author). 29 refs, 8 figs