عنوان مقاله [English]
نویسندگان [English]چکیده [English]
Brachytherapy is one of the most effective methods in the treatment of local malignant tumors. In this study, dosimetric parameters of 103Pd brachytherapy source Theragenics model 200 was estimated according to TG-43U1 protocol using GATE 8.1 Monte Carlo code. At first, validation of the GATE simulation for the seed was performed by some criteria consist of radial dose function and 2D anisotropy function inside liquid water according to the AAPM TG-43U1 recommendations. The maximum average deviations were found to be about 9% and 8% for radial dose function and anisotropy function, respectively. On the other hand, since the attenuation coefficient of the sources in the water phantom is different from that of various tissues, the effects of the various tissues on the radial dose function parameter of the 103Pd brachytherapy source were investigated using GATE 8.1 code. The relative deviation values of the radial dose function in the adipose, muscle, breast, and brain tissue compared with water phantom in the radial distance of 5cm were about 153%, 30%, 35%, and 29%, respectively. There is a good agreement between the results of this work and other study in calculation of dosimetric parameters of brachytherapy 103Pd source base on the recommendations of TG-43U1 protocol. The results show that the dosimetric parameters of 103Pd brachytherapy source can be accurately calculated using the GATE code in spite of low energy of radiation and high variation in dose rate with increasing distance from the center of the source. On the other hand, the results of the dose calculation in different phantom could be used in the clinical treatment planning systems.