39 Use of the GATE/GEANT4 platform in high dose rate brachytherapy: Dosimetric study of a Cobalt 60 source

Abstract

Introduction The Monte-Carlo GATE/GEANT4 simulation platform offers a powerful tool for dosimetry applications in brachytherapy [1] . This work aims to use this platform to study the dosimetric parameters of a source of Cobalt-60 used in high dose rate brachytherapy (HDR). Methods In this work a source of cobalt 60 (model Co0-A86 from Eckert & Ziegler BEBIG) was simulated by the platform GATE/GEANT4 version 7.2. In a first step, all dosimetric parameters: dose rate constant, air kerma strength, radial dose function and anisotropy function were studied according to the recommendations of the AAPM (American Association of Physicists in Medicine) Working Group No. 43 [2] and the report of AAPM and ESTRO [3] (European Society for Radiotherapy & Oncology). In a second step, a simulation of the dose profile curves was performed on different axes of the source. In addition, we reproduced the results of the simulation of the profiles on the treatment planning system HDRPlus (Eckert & Ziegler BEBIG). The comparison of the profiles is done by the tool gamma-index [4] . Results For the parameters of the TG-43 formalism, the results obtained show a good agreement between the GATE/ GEANT4 platform and the studies taken as reference [5] , [6] . For the comparison of the dose profiles a gamma-index of 100% was obtained for 2% difference-in-dose criteria and DTA (Distance-To-Agreement) of 2 mm. Conclusions This work shows that the GATE/GEANT4 simulation platform can be a reliable tool for high dose rate (HDR) brachytherapy dose distribution calculations.