Radiation beam characteristics of a 22 MeV microtron

The properties of the electron and photon beams from a 22 MeV clinical microtron are presented. Favourable isodose distributions for radiation therapy are obtained for both modalities. For the electron beam this is accomplished using a dual scattering foil system in which the secondary foil is shaped to optimize uniformity and minimize energy loss and energy straggling. The photon beam is flattened by a composite filter to produce dose distributions of high uniformity over a wide depth interval. (Auth.)