Optical investigation of MAGAT polymer gel dosimeter embedded with methylene blue dye and zinc oxide nanoparticles using UV/Vis spectrometry pre- and post-irradiation of 6MV photon beam

Among methacrylic acid-based gel dosimeters, the MAGAT hydrogel stands out for its tissue equivalence, making it a promising candidate for clinical applications. The incorporation of methylene blue (MB) or zinc oxide nanoparticles (ZnO NPs) into MAGAT hydrogel aims to improve its formulation, enhance dose absorption and facilitate detailed 3D dose verification. The optimization of MB and ZnO NPs has not yet been investigated with polymer gel before. We studied MAGAT hydrogel dosimeters with varying MB concentrations (0.001, 0.002, 0.003, 0.01, 0.02, and 0.03% w/w) and ZnO NPs concentrations (0.03–0.07% w/w), using a double-beam spectrophotometer for optical measurements. Our findings identified the optimal MB concentration in the MAGAT + MB formulation at 0.001% w/w, achieving a sensitivity of 0.0285 a.u./Gy and an accuracy of 0.9995. For the MAGAT + MB + ZnO NPs formulation, the optimal ZnO NPs concentration was 0.07% w/w, with a sensitivity of 0.03106 a.u./Gy and an accuracy of 0.9945. The absorbance peaks for both optimum formulations of (MAGAT + MB) and (MAGAT + MB + ZnO NPs) were observed at a wavelength of 665 and 668 nm, respectively. These advancements promise to reduce monitor units, ensure precise dose delivery, shorten treatment times, and minimize treatment errors.