Novel dose calculation and characterization of 32P intravascular brachytherapy stent source

Abstract

Abstract Derived from AAPM task group No. 60/149 protocol, applicable in treatment planning In this study, the two-dimensional dose distributions in water for a 32P intravascular brachytherapy stent have been calculated. The pure beta emitter source 32P which has been coated on Palmaz-Schatz stent is discussed. The dosimetric parameters required by the AAPM TG-60/149 formalism are discussed and calculated. Version 5 of the (MCNP) Monte Carlo radiation transport code was used to calculate the dosimetry parameters around the source. The Monte Carlo calculated dose rate at the reference point is found to be 2.8 Gy/μCi. Also in this study, the geometry function, G(r,θ), radial dose function, g(r), and the anisotropy function, F(r,θ), have been calculated at distances from 1.8 to 9 mm. The results of these calculations have been compared with other published calculated and measured values for an actual same source. High dose variants were visible near the 32P stent surface, but these values decreased with depth in water rapidly. There is an acceptable agreement between the calculated data in this study and other published data for the same source, which validate our simulations method.