Preliminary study on a new 3D radiochromic KI-Pluronic F-127 gel dosimeter for radiotherapy

Abstract

This work concerns a new potassium iodide based radiochromic gel dosimeter with Pluronic F-127 gel matrix. The optimal dosimeter composition obtained in this work comprises 200 mM potassium iodide as a radiation sensitive colour changing compound, 200 mM fructose, 50 mM gluconic acid δ-lactone and 25% (w/w) poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide) (Pluronic F-127) as a physical gel matrix. The potassium iodide changes from colourless to yellow colour upon ionizing radiation and the intensity of colour increases with an increase of radiation dose. The dosimeter after irradiation was measured using UV-Vis spectrophotometry to derive basic characteristics related to dose response: threshold dose, linear and dynamic dose response, dose sensitivity as well as stability over time after irradiation. Water equivalence was also analysed with respect to other similar 3D radiochromic gel dosimeters for a broad photon energy range. The results obtained indicate that the KI-Pluronic F-127 radiochromic gel dosimeter shows potential for use in 3D radiotherapy dosimetry.