Determining beta radiation doses from Y-90 microsphere for the treatment of hepatic tumors by using Monte Carlo and analytical methods

Abstract

The very short range of beta radiation is a potential radiation treatment for tumor, which can preserve sensitive structures. However, due to the limited range of beta radiation, practical dosimetry of beta sources may be a point of concern, and theoretical dosimetry methods play an important role. A resin microsphere loaded with the Yttrium-90 (Y-90) radionuclide can be applied in the radioembolization of hepatic tumors. In this work, we present initial calculations of dose rates around a microsphere loaded with the Y-90 radionuclide uniformly distributed on its exterior surface. Two approaches were used to carry out the estimations: the first one by means of Monte Carlo simulations using the PENELOPE code and the second one by means of the beta-point dose function formalism. A Fortran code was developed to handle with the various quantities necessary to perform the numerical integration of the beta-point dose function. A comparison between results obtained by means of both methods indicated a maximum difference of ~5% up to the 0.3 cm distance from the center of the sphere.