Dosimetric comparison between microSelectron iridium-192 and flexi cobalt-60 sources in high-dose-rate brachytherapy using Geant4 Monte Carlo code.

The primary photons from the lower-energy HDR microSelectron Ir source have a limited range and are partially attenuated when considering the results of radial and anisotropic dose distribution functions. This implies that a HDR flexi Co radionuclide could be used to treat tumors beyond the source compared with a HDR microSelectron Ir source, despite the fact that Ir has a lower exit dose than HDR flexi Co radionuclide source.