Dosimetric investigation of high dose rate Ir-192 source with Monte Carlo method

Background: this study aims to calculate the air-kerma strength (sk),the dose rate constant (∧) and the dose rate profiles of a gammamed 12i ir-192 source by using the monte carlo technique and to compare the dose rate values with those calculated by the abacus hdr treatment planning system (tps). materials and methods: air-kerma strength (in units of u; 1 u= μgy m2 h-1) and the dose rate constant (∧) of a gammamed 12i ir-192 source were computed with the monte carlo-based code mcnp. for a single dwell posi4on,profiles of dose rate per air kerma rate strength (in unit of u) along the x axis were obtained with mcnp and compared with data from the abacus tps at y=0,1,and 2 cm. results: the air-kerma strength and the dose rate constant of the source were calculated to 9.98×10-8 u and 1.106 cgy h-1 u-1,respec4vely. the maximum dose differences between mcnp and tps along the x axis were found to be 1.3,3.7 and 5.4% at distances more than 1 cm away from the source center for y= 0,1 and 2 cm planes,respec4vely. conclusion: the dose rate profiles calculated with mcnp and by the tps show good agreement except for points located beyond the 4p of the source.