Dosimetry and Radioenhancement Comparison of Gold Nanoparticles in Kilovoltage and Megavoltage Radiotherapy using MAGAT Polymer Gel Dosimeter

Background: Numerous unique characteristics of the nanosized gold, including high atomic number, low toxicity, and high biocompatibility make it one of the most appropriate nanostructures to boost radiotherapy efficacy. Many in-vivo and in-vitro investigations have indicated that gold nanoparticles (AuNPs) can significantly increase tumor injuries in low kilovoltage radiotherapy. While deep-lying tumors require much higher energy levels with greater penetration power, and investigations carried out in megavoltage energy range show contradictory results. Objective: In this study, we quantitatively assess and compare dose enhancement factors (DEFs) obtained through AuNPs under radiation of Cobalt-۶۰ source (۱.۲۵MeV) versus Iridium-۱۹۲ source (۳۸۰ KeV) using MAGAT gel dosimeter. Material and Methods: MAGAT polymer gel in both pure and combined with ۰.۲ mM AuNPs was synthesized. In order to quantify the effect of energy on DEF, irradiation was carried out by Co-۶۰ external radiotherapy and Ir-۱۹۲ internal radiotherapy. Finally, readings of irradiated and non-irradiated gels were performed by MR imaging. Results: The radiation-induced R۲ (۱/T۲) changes of the gel tubes doped with AuNPs compared to control samples, upon irradiation of beams released by Ir-۱۹۲ source showed a significant dose enhancement (۱۵.۳۱% ±۰.۳۰) relative to the Co-۶۰ external radiotherapy (۵.۸۵% ±۰.۱۴). Conclusion: This preliminary study suggests the feasibility of using AuNPs in radiation therapy (RT), especially in low-energy sources of brachytherapy. In addition, MAGAT polymer gel, as a powerful dosimeter, could be used for ۳D visualization of radiation dose distribution of AuNPs in radiotherapy.

کلیدواژه ها:

Brachytherapy ، Dose Enhancer ، External Radiotherapy ، Gel Dosimetry ، Nanotechnology