The Applicability of Pions to Cancer Radiotherapy I. Experimental Measurements of the Capture and Absorption of Pions in Polymer

Abstract

A future application of negative pions to radiotherapy has arrived at a promising stage. Negative pions, in addition to their good localization characteristics, offer an advantage of favorably influencing biological factors because of differences in the quality of radiation given to a) the treatment volume and b) the intervening normal tissue. By utilizing dose fractionation, the low dose to intervening normal tissue with its low LET allows these tissues to recover better than cells in the treatment volume. In this study the lucite phantom was bombarded with 150 MeV/c and 173 MeV/c negative pions and 173 MeV/c positive pions, respectively, by using the 12GeV proton synchrotron of the National Laboratory for High Energy Physics (KEK). Range-energy relations in the lucite and the remaining curves of pions were observed. The observed range of pions in lucite agreed well with the theoretical prediction. The remaining curves show the different structures for π⁺ and π^- mesons. Peak to plateau ratio is ten times.