No 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.

This study aims to determine AAPM TG-60 dosimetric quantities in regions surrounding the 103Pd stent wall by MCNP5 Monte Carlo code. The Palmaz-Schatz stent was modeled by a hollow cylinder of 17.89mm length (2mm diameter) with net surface very similar to real stent. The Dose deposited per photon (Gy), relative dose, Anisotropy function, F(r,θ), and radial dose function, gL(r), were described at AAPM TG-60 protocol were generated from these values and listed in tabular format. For benchmarking, the relative dose values were verified with TG-43 and EGS4 code results at identical conditions, relative to the radial distances from surface of the stent. There were noticeable results. These physical dosimetric parameters can be used in future treatment planning systems for IVBT.