Monte Carlo Dosimetric Study of the GZP 60Co Brachytherapy Source with Stainless Steel Applicator

Objective\r\nTo evaluate the effect of stainless steel applicator on dose distribution in GZP 60Co brachytherapy source and to obtain the dosimetric parameters of the 60Co source with stainless steel applicator.\r\n\r\n\r\nMethods\r\nGeant4 was employed to obtain the mean adsorption dose of the 60Co brachytherapy source in the range of 0-10 cm, and the dosimetric parameters were calculated according to the formula proposed by AAPM reports TG43 and TG43U1. The 60Co source was located in the center of a sphere water phantom with a radius of 30 cm.\r\n\r\n\r\nResults\r\nFor channel 1 and 2 of GZP 60Co source, the results of Λ with stainless steel applicator were 1.014 cGyh-1U-1(with a difference of 0.5% compared with non-applicator), the results of Λ with stainless steel applicator for channel 3 were 0.998 cGyh-1U-1(with a difference of 0.1% compared with non-applicator). The radial dose function in the range of 0.5-10.0 cm in a longitudinal direction was calculated and the fitting formula for the function was obtained. The polynomial function for the radial dose function and the anisotropy function with a of 0°-175° and an r of 0.5-10.0 cm were obtained.\r\n\r\n\r\nConclusion\r\nThe dosimetric parameters of the 60Co source with stainless steel applicator are obtained, which provide more accurate reference data for clinical application. In clinical practice, the effect of stainless steel applicator on dose distribution should be considered.\r\n\r\n\r\nKey words: \r\n60Co brachytherapy source; Stainless steel applicator; Dosimetric parameter