Fundamental dose distribution for interstitial irradiation with Au grains

A principle of radiation therapy is to determine a proper dose distribution for tumor localization. In this paper we present several models of arranging Au grains for interstitial irradiation and discuss characteristics of their dose distributions. Au grains were arranged in a lattice of three by three for evaluation of isodose curves on a source plane and several planes parallel to it. Intersource distances were varied to determine adequate distances for ideal dose distributions for tumor control. Through this study, we concluded that the most favorable intersource distance for effective dose distribution was 1.0-1.25 cm. We also found that interstitial irradiation with Au grains was hard to apply to deeply spreading tumors.