en Radiation Biology Radiation Biology تحقيق بديع Original Research <strong>Background:</strong> The Monte Carlo (MC) method is not only used for dose calculations around brachytherapy sources but also for benchmarking treatment planning systems (TPS) calculations. <strong>Materials and Methods:</strong> 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. <strong>Results:</strong> 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. <strong>Conclusion:</strong> 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. Brachytherapy, high dose rate (HDR), 60Co, Monte Carlo. 181 186 http://ijrr.com/browse.php?a_code=A-10-1-255&slc_lang=en&sid=1 A. Mesbahi asgharmesbahi@yahoo.com 79003194753284600907 79003194753284600907 Yes