Takashi Kitabatake

Scattering Foil Device for High-Energy Electron-Beam Therapy

During the past decade, treatment-planning for high-energy electron-beam therapy has progressed along various lines to achieve homogeneous irradiation of tumor, with minimum damage to surrounding normal tissue. One of the most frequently used methods is an absorption technic in which a water-equivalent substance is interposed in the end of a collimator system (8, 11, 13, 14, 16–18). The distribution of beam intensity is thus well adjusted to the individual case for any single fixed field. With the absorbing material in the end of a treatment cone, however, the limited skin-sparing effect is lost because of secondary radiation. The benefits of high-energy radiation without the disadvantage of such absorbing material are desirable. This is a report of an evaluation of a special device consisting of scattering foil to alter the intensity of the betatron electron beam. Isodose curves for clinical use were measured and compiled. Method A betatron3 operating in the 4 to 31 MeV energy range was used in this stud...