Gel dosimeters are attractive detectors for radiation therapy, with properties similar to biological tissue and the potential to visualize volumetric dose distributions. Radio-fluorogenesis is the yield of fluorescent chemical products in response to energy deposition from ionizing radiation. This report shares the development of a novel radio-fluorogenic gel (RFG) dosimeter, gelatin infused with coumarin-3-carboxlyic acid (C3CA), for the quantification of imparted energy. Aqueous solutions exposed to ionizing radiation result in the production of hydroxyl free radicals through water radiolysis. Interactions between hydroxyl free radicals and coumarin-3-carboxylic acid produce a fluorescent product. 7-hydroxy-coumarin-3-carboxylic acid has a blue (445 nm) emission following ultra-violet (UV) to near UV (365–405 nm) excitation. Effects of C3CA concentration and pH buffers were investigated. The response of the RFG was explored with respect to strength, type, and exposure rate of high-energy radiation. Results show a linear dose response relationship independent of energy and type, with a dose-rate dependency. This report demonstrates increased photo-yield with high pH and the utility of gelatin-RFG for phantom studies of radiation dosimetry.

Abstract:In radiotherapy, accurate deposition of energy to the targeted volume is vital to ensure 9 effective treatment. Gel dosimeters are attractive detection systems, as tissue substitutes with 10 potential to yield three-dimensional dose distributions. Radio-fluorogenesis is creation fluorescent 11 chemical products in response to energy deposition from high-energy radiation. This report shares 12 studies of a radio-fluorogenic gel dosimetry system, gelatin with coumarin-3-carboxlyic acid 13 (C3CA), for the quantification of imparted energy. Aqueous solutions exposed to ionizing radiation 14 result in the production of hydroxyl free radicals through water radiolysis. Interactions between 15 hydroxyl free radicals and coumarin-3-carboxylic acid produce a fluorescent product.