A surface bolus material for high-energy photon and electron therapy.

Abstract

A useful bolus material was described for therapy with high-energy photons and electrons (> 1 MeV). Qualities evaluated included flexibility, transparency, tissue equivalence (re radiation interactions), stability at high doses, durability, lack of toxicity, ease in cleaning, low flammability and cost. Using a parallel-plate ionization chamber and 60Co, 4-, and 10-MV photons as well as 6- and 18-MeV electrons, maximum deviation from water-equivalent values was .apprx. 2 mm for 6-MeV electrons. The material comes in large sheets of precise thickness (.+-.0.5 mm) which can be cut and layered to form more complex shapes.