Determination of TG-۴۳ dosimetric parameters for I-۱۲۵, Ir-۱۹۲ and Co-۶۰ brachytherapy sources using the Monte Carlo simulation

It is important to have accurate information regarding the dose distribution for treatment planning and to accurately deposit that dose in the tissue surrounding the brachytherapy source. However, the practical measurement of dose distribution for various reasons is associated with several problems. In this study, ۶۷۱۱ I-۱۲۵, Micro Selectron mHDR-v۲r Ir-۱۹۲, and Flexisource Co-۶۰ sources were simulated using the MCNP۵ Monte Carlo method. To simulate the sources, the exact geometric characteristics of each source, the material used in them, and the energy spectrum of each source were entered as input to the program, and finally, the dosimetric parameters including dose rate constant, radial dose function, and anisotropy function were calculated for considered seeds according to AAPM, TG-۴۳ protocol recommendation. Results obtained for dosimetric parameters of dose rate constant, radial dose function, and anisotropy function for I-۱۲۵, Ir-۱۹۲, and Co-۶۰ sources agreed with other studies. According to the good agreement obtained between the parameters of TG۴۳ and other studies, now these datasets can be used as input in the treatment planning systems and to validate their calculations.

Keywords:

Brachytherapy , Dosimetric parameters , TG-۴۳ protocol , Monte Carlo simulation , MCNP۵ code