Study of the Optimal Composition and Storage Conditions of the Fricke-XO-Pluronic F-127 Radiochromic Dosimeter.

Michał Piotrowski,Marek Kozicki,Piotr Maras,Sławomir Kadłubowski

doi:10.3390/ma15030984

Michał Piotrowski, Marek Kozicki + Show 2 more

Open Access

https://doi.org/10.3390/ma15030984

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Abstract

This paper presents the results of research on the Fricke–XO–Pluronic F–127 dosimeter. It consists of a Fricke dosimetric solution and xylenol orange (XO), which are embedded in a matrix of poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide) (Pluronic F–127). Upon irradiation, Fe+2 ions transform into Fe+3, forming a colored complex with XO ([XO-Fe]+3). The color intensity is related to the dose absorbed. The optimal composition, storage conditions, and radiation-induced performance of the Fricke–XO–Pluronic F–127 dosimeter were investigated. The optimal composition was found to be 1 mM FAS, 50 mM sulfuric acid (H2SO4), 0.165 mM XO in 25% Pluronic F–127. The basic features of this dosimeter are discussed, such as dose sensitivity, linear and dynamic dose range, stability before and after irradiation, storage conditions, dose response for irradiation with 6 and 15 MV photons, and batch-to-batch reproducibility. The obtained results showed a certain potential of the Fricke–XO–Pluronic F–127 for radiotherapy dosimetry.

Highlights

In addition to the above-mentioned matrices for the preparation of Fricke 3D gel dosimeters, an alternative matrix has been proposed. It is based on poly(ethylene oxide)block-poly(propylene oxide)-block-poly(ethylene oxide) (Pluronic F–127) [25], which creates physical gels with a high degree of transparency and colorlessness, allows to prepare a Fricke gel dosimeter at low temperatures due to the phase behavior of the Pluronic F–127; it is stable over a wide temperature range and has been proven to be non-toxic [26,27]
Fricke–xylenol orange (XO)–Pluronic F–127 dosimeter: (i) what is the influence of the storage method on the stability of the dosimeter and (ii) how the availability of oxygen affects the stability of the dosimeter
Fricke–XO–Pluronic F–127 samples in cuvettes filled to about 90% volume of the cuvette covered with a plastic cap, and in cuvettes filled in completely and tightly closed were stored at room temperature with protection from daylight, at room temperature with access to daylight and at low temperature (4 ◦ C) without access to daylight

Summary

Introduction

The first mentions of 3D radiotherapy based on a standard Fricke dosimetric solution embedded in a polymer matrix come from the 1980s [1,2]. This dosimeter was measured with magnetic resonance imaging. In addition to the above-mentioned matrices for the preparation of Fricke 3D gel dosimeters, an alternative matrix has been proposed It is based on poly(ethylene oxide)block-poly(propylene oxide)-block-poly(ethylene oxide) (Pluronic F–127) [25], which creates physical gels with a high degree of transparency and colorlessness, allows to prepare a Fricke gel dosimeter at low temperatures due to the phase behavior of the Pluronic F–127; it is stable over a wide temperature range and has been proven to be non-toxic (approved by the Food and Drug Administration, FDA, Silver Spring, MD, USA) [26,27].

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