Calculation of Dose Distribution Around a Clinical 252Cf Source for Neutron Therapy Based on AAPM, TG-43 Protocol
Ali Yadollahpour1, Mansour Zabihzadeh1,2* and FoadGoli Ahmadabad31Department of Medical Physics, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran. 2Department of Radiation Oncology, Golestan Hospital, Ahvaz, Jundishapur University of Medical Sciences, Ahvaz, Iran. 3Department of Medical Physics, School of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran.
Abstract: Determining dose distribution around the brachytherapy sources is crucial to establish an accurate treatment planning. In this study dosimetric parameters of 252CF as neutron brachytherapy source were calculated using Monte Carlo simulation method.Physical and geometrical parameters of 252CF source were simulated by MCNPX (2.6.0)modeling code. Air kerma strength, Sk, of source positioned inside a vacuum sphere was calculated. Recommended dosimetric parameters by AAPM, TG-43 protocol were calculated by centering source in a homogeneity phantom.The air kerma strength of 252CF source was estimated 0.345 (cGycm2/¼gh). Dose rate constant was 7.014 cGyh-1U-1. The Radial dose function with 5 degree equation was estimated by gN(r) = 1.1745+0.2298r+0.061r2+-0.0109r3+0.0009r4+-3E10-5r5. Numerical amounts of the anisotropy dose functions and the related equations were calculated.Despite low-energy emission photons and high dose gradients with radial distance, dosimetric parameters of the model 6711 I-125 source can be calculated by MCNPX Monte Carlo code with acceptable accuracy. Calculated parameters of the model 6711 I-125 brachytherapy source can be used by treatment planning systems for brachytherapy.
Keywords: Brachytherapy; Neutron dosimetry; 252CF Source; Monte Carlo Simulation Back to TOC