Introduction: According to recommendations of AAPM and ESTRO (2007), dosimetric characteristics of HDR brachytherapy sources with average energy higher than 50 keV should be determined either using Monte Carlo calculation or experimental methods by investigators who are independent of the vendor, and should be published in peer-reviewed journals. For conventional sources, a single dosimetric study, preferably Monte Carlo calculation, is sufficient (AAPM and ESTRO report, 2012). Recently, 60Co source with commercial name Co0.A86 BEBIG was entered to Iran and relevant equipment was installed in several institutes including Reza Radiotherapy and Oncology Center (RROC). In accordance with AAPM and ESTRO, 2012 (section VI, par.2), the medical physicist should check the accuracy of dose calculations and verify dosimetric parameters in TPS. Methods: The Monte Carlo calculation in this study was based on the formalism introduced in TG-43U1 and the report of AAPM and ESTRO (2012). Hereupon, the computation required a prolonged run time (~6 months) using 64 CPU core. Results: TG-43 parameters for use in TPS were obtained and compared with existing datasets. Furthermore, the dose calculated using the new dataset was compared with that obtained from BEBIG HDRplus for one case. Discussion and conclusion: AAPM and ESTRO (2012) recommended a consensus dataset based on studies that suffer from underestimation of the dose rate nearby the transverse axis and asymmetry at large distances from the source. In response to this report, a study was conducted in 2014 to address these shortcomings. However, using PENELOPE code with its non-updated cross section dataset in the energy range of photons emitted by 60Co lead to uncertainties that could be removed from dose calculations. This study attempted to eliminate all resources of either type A or B uncertainties (introduced in TG-138) and this findings underline the necessity to use the new dose library.

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