Elucidation of poly(vinyl alcohol) and iodide gel dosimeter characteristics by predicting changes in radical concentrations and measuring responsiveness to heavy ion beams

Three-dimensional (3D) gel dosimeters enable a more practical radiation measurement and are expected to be widely used as a new measuring instrument. Herein, we investigate a type of 3D gel dosimeter, the poly(vinyl alcohol) and iodide (PVA-I) gel dosimeter. This gel can perform 3D dose distribution measurements by forming a red-colored complex of I3− and PVA when irradiated. We previously developed a leuco crystal violet (LCV) micelle gel dosimeter and measured its reactivity to heavy ion beams. However, the amount of color developed near the Bragg peak decreased, and the dose was underestimated. In this study, we used a PVA-I gel dosimeter to measure the dose distribution of heavy ion beams and compared the results with those of the LCV micelle gel dosimeter. We also examined the gels’ reactivity to heavy ion beams by simulating changes in the radical concentrations in the gel, using Monte Carlo calculations. The findings of this study demonstrate that the PVA-I gel dosimeter has a higher responsiveness near the Bragg peak than the micelle gel dosimeter and can be used as a dosimetry device for heavy ion beams. •PVA-KI gel can be used as a dosimetry device for heavy ion beams.•PVA-KI gel is more responsive than micelle gel for heavy ion beam dosimetry.•PVA-KI results are reproducible across two irradiations and thus can be reused.•Simulations of changes in radical concentrations provide mechanistic insights.