FRICKE DOSIMETRY: A NEW METHODOLOGY TO CALCULATE THE RADIATION CHEMICAL YIELD VALUE FOR 192IR HDR SOURCES

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All articles of this category (opens in new window) The Fricke dosimeter is the most used liquid chemical dosimeter. High dose rate (HDR) brachytherapy using 192Ir sources is an important treatment option and it has been shown to be a feasible option for the absorbed dose standard. One of the parameters used to determine the absorbed dose at the Fricke solution is the G-value (G(Fe3+)). This parameter is crucial and can be defined as the number of molecules of Fe+3 produced per Joule of energy absorbed in the solution. Few authors have determined the G-value for energies below the 60Co. Most part of papers on the literature compares the G-value to 60Co and different beam qualities. The G-value for energies lower than Co-60 are not well defined, some authors obtained it through calorimetric measurements and others the G(Fe3+) was obtained from the empirical formalism based on the primary products and Linear energy transfer (LET) values. The present work aims to determinate the G-value for 192Ir HDR using a new setup elaborated by Radiological Sciences Laboratory group (LCR/UERJ-Rio de Janeiro State University, Rio de Janeiro, Brazil). It was performed using a HDR brachytherapy using 192Ir source (GammaMed Plus HDR 232, Varian) at Radiotherapy department of HUCFF - Hospital Universitário Clementino Fraga Filho, Rio de Janeiro, Brazil. The results showed a good statistical response to doses about 22 Gy with a dose rate of 0.01Gy.s-1. The G value calculated was 1.5510-6 mol.J-1 and type A uncertanty 0.96%. Publication History Article published online: 11 March 2025 © 2018. This is an Open Access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Thieme Revinter Publicações Ltda. Rua do Matoso 170, Rio de Janeiro, RJ, CEP 20270-135, Brazil

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