Evaluation of diffusion properties of polyethylene oxide (PEO) based dosimetric gel

Volumetric chemical dosimetry with gel-based radiation detectors using Fricke or polymer-based materials provides a unique methodology for measuring dose distribution in three dimensions, positioning itself as a promising alternative to the use of radiographic films and ionization chambers in radiotherapy. However, problems such as the heterogeneity of natural gelatinous matrices and diffusion of ferric ions in traditional Fricke gels can lead to significant uncertainties in spatial dose measurements. Therefore, developing new dosimetric gel formulations based on synthetic matrices that offer high stability, sensitivity, reproducibility, and ease of production is crucial. The main objective of this study was to standardize the production method of a chemical dosimeter based on polyethylene oxide (FX-PEO) and analyze the stability of its response as well as other essential factors to validate its performance using UV-Vis spectrophotometry for optical absorbance and nuclear magnetic resonance. Preliminary results demonstrate that the diffusion coefficient of the PEO-based polymer Fricke gel is approximately 45 % lower than that of the Fricke Xylenol gel, significantly contributing to the enhanced performance of the detector in radiotherapy applications.