Authors
Abstract
Background: One of the ways to treat prostate cancer is brachytherapy using low-energy sources, such as iodine-125 (125I). The purpose of this study was to assess dose enhancement factor in tumors in the presence of various nanoparticles in prostate tumor, and the effect of these nanoparticles on isodose curves in prostate cancer brachytherapy using Monte Carlo simulation.
Materials and Method: 125I brachytherapy source model SL-125/SH-125 was simulated using Monte Carlo MCNPX code. TG-43 parameters were calculated and verified. Dose enhancement factors were evaluated in presence of Fe2O3, Ag, Gd, Pt and Au nanoparticles in central cross section of the tumor in concentrations of 7, 18 and 30 mg/ml.
Results: Dose rate constant obtained 0.954 cGyh-1U-1. Maximum dose enhancement factors for Fe2O3, Ag, Gd, Pt and Au were 1.79, 1.32, 1.14, 1.15 and 1.27, respectively. Also, the 100% isodose line shifted toward the central point of the spherical tumor and the 100% isodose line shifted outward. Dose enhancement factors had no rule in increasing or decreasing by atomic number of nanoparticles.
Conclusion: Regarding to the simulation results, it can be concluded that nanoparticles presence in tumor leads to dose increase inside the tumor and dose decrease outside the tumor. Therefore, we can reduce treatment time and activity. So, the clinical use of these nanoparticles is recommended to enhance prostate brachytherapy dose.
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