Radial dose functions of GZP6 intracavitary brachytherapy 60Co sources: treatment planning system versus Monte Carlo calculations

Background: The Monte Carlo (MC) method is not only used for dose calculations around brachytherapy sources but also for benchmarking treatment planning systems (TPS) calculations. Materials and Methods: Three 60Co sources of GZP6 brachytherapy unit were simulated using MCNP4C MC Code. The radial dose functions were calculated by MC method and GZP6 TPS and were compared. Results: There was a good agreement between MC and TPS calculations for all sources. Discrepancies up to 10% were observed for points close to the sources, but for those farther than 7mm from source center, differences were less than 2% for all sources. Conclusion: Our results showed that GZP6 TPS calculations can accurately be used for dose calculations in brachytherapy treatments for points farther than 7mm from the source center.