Monte Carlo dose calculation for HDR brachytherapy source using EGS5 code

Brachytherapy is a technique of irradiation for cancer treatment. It involves placing radioactive sources as close as possible to the tumor. The various types of available sources vary according to their geometry, and the isotope selected (192Ir, 125I, 60Co…). Dosimetric parameters for brachytherapy source should be known before its effective clinical practice. For this reason, there are several source geometries and mediums where the authors calculate the parameters of brachytherapy sources recommended by TG-43U1 protocol, using Monte Carlo codes. In this work, the simulated geometry of the BEBIG 60Co HDR source model Co0.A86 was performed through the Monte Carlo method using the EGS5 code, and the dose rate distribution around the HDR source has been determined. Before starting the simulations, geometry modelling for the studied source is necessary. Thus, CGVIEW was employed for checking the scoring zones and the mediums and validating calculation conditions for the source. Otherwise, the dosimetric parameters, the radial dose function gL(r) for the distance of 0.25 cm to 20 cm and anisotropy function F(r,θ) with the range of 0° to 179°, were calculated using the dose calculation formalism and the output files of EGS5 code. The results of EGS5 Monte Carlo simulations were presented in tabulated and graphical formats and compared with other works in which the authors use other Monte Carlo codes such as GEANT4 and PENELOPE. Good agreement with the published data was observed, except the values close to the ends of the source (<10° and >160°) for the anisotropy function and the low value r = 0.25 cm for the radial dose function.