Document Type : Original Research
Authors
1 Department of Medical Physics and Biomedical Engineering, School of Medicine, Tehran University of Medical Sciences (TUMS), Tehran, Iran
2 Cancer Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, Iran
Abstract
Background: Polymer gels provide high-resolution Three-Dimensional (3D) dosimetry and serve as valuable tools for quality assurance in radiotherapy.
Objective: The current study aimed to synthesize a Methacrylic Acid with Gelatin, Initiated by Copper, and Agarose (MAGICA) added polymer gel dosimeter doped with Bismuth Nanoparticles (BiNPs) and to evaluate its dosimetric performance under clinical megavoltage irradiation systematically.
Material and Methods: In this experimental study, we prepared MAGICA gels containing BiNPs at concentrations of 0.05, 0.1, and 0.2 mM, along with control gels. These gels were then simultaneously irradiated with 6 MV photon beams from a clinical linear accelerator. The dosimetric responses were quantified using T₂-weighted magnetic resonance imaging (MRI).
Results: All samples exhibited a stable linear R₂–dose response, and the incorporation of BiNPs enhanced the dosimetric sensitivity. Analysis of the Dose Enhancement Factor (DEF) yielded values of 1.05, 1.09, and 1.08 for the 0.05, 0.1, and 0.2 mM BiNP concentrations, respectively. This enhancement is attributed to increased local energy deposition and production of hydroxyl radicals via water radiolysis.
Conclusion: BiNP-doped MAGICA gel provides improved dosimetric performance and reproducibility, establishing it as a robust platform for 3D dose verification and a promising candidate for preclinical radiotherapy optimization.
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