Abstract
Abstract
The study employs the Monte Carlo method to calculate the internal dosimetry of beta, beta/Auger and alpha-type decaying radionuclides used in the treatment of prostate cancer. The distributions of dose to the prostate and critical organs were simulated on a virtual phantom using GATE MC software. In GATE simulation, geometric parameters and densities were determined for the prostate as the source organ and the kidneys, liver, testicles, and bladder as critical organs. In the prostate geometry, Lu-177, Ac-225, and Tb-161 with an activity of 370 MBq were identified. Using the DoseActors command, the S values, instant absorbed doses (Gy/s), uncertainties, and total absorbed doses (Gy) were computed and saved as an output file in the TXT format. Dosimetric comparison was made between different TRTs according to the absorbed doses in the source and critical organs. The prostate was found to be the tissue that received the highest instant absorbed dose with 8.397E-03, 1.594E+00 and 1.195E-02 Gy/s for Lu-177, Ac-225 and Tb-161, respectively. The kidney, liver, and testicles were taken lowest instant absorbed doses with 3.888E-08 (mean), 5.679E-08, and 4.302E-07 (mean) Gy/s by Tb-161. Lu-177 gave the lowest instant absorbed doses of 5.731E-07 Gy/s for the bladder. It was found that there was no overdose in any critical organ according to the critical threshold values given to protect the organs from radiation-related toxic effects. However, testicles were additionally evaluated in terms of fertility. Ac-225 and Tb-161 were radionuclides that produced optimal doses for TRT.