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Dosimetry aspects of a non-diffusing genipin–gelatin gel

Citation

Davies, JB and Bosi, SG and Baldock, C, Dosimetry aspects of a non-diffusing genipin-gelatin gel, Radiation Physics and Chemistry, 83 pp. 19-27. ISSN 0969-806X (2013) [Refereed Article]

Copyright Statement

Copyright 2012 Elsevier

DOI: doi:10.1016/j.radphyschem.2012.09.018

Abstract

Genipin–gelatin gel shows promise as a stable, three-dimensional dosimeter for use in quality assurance for radiotherapy treatments. Genipin creates cross-links in gelatin, forming a blue colour that bleaches quantitatively upon irradiation. A formulation suitable for dosimetry was investigated by varying the concentrations of genipin, gelatin and sulphuric acid and determining the dose sensitivity. An important parameter of the gel preparation that affects dose sensitivity is the temperature at which the cross-linking reaction takes place. The most suitable formulation for dose measurements in 1 cm pathlength cuvettes was found to be made from 50 μM genipin, 4% w/w gelatin and 100 mM sulphuric acid in the final gel. An evaluation of the diffusion coefficient of chromophores in this gel dosimeter demonstrated that this genipin–gelatin gel is a non-diffusing dosimeter. This dosimeter was also evaluated for stability, dose sensitivity, irradiation and measurement temperature dependence and dose rate dependence. No appreciable dependence on dose rate in the range 0.4–40 Gy min−1 was found. No appreciable dependence on measurement temperature between 15 and 23 °C was found. A slight dependence on irradiation temperature was found and this was used to determine the product of the molar linear absorption coefficient and the radiation chemical yield. Finally, the dosimeter measurement uncertainty was evaluated and this was used to determine the dose resolution. Although the focus of this work is on a genipin–gelatin gel dosimeter, the measurement and calibration techniques presented may be applied to any gel dosimetry system measured spectrophotometrically.

Item Details

Item Type:Refereed Article
Keywords:genipin, gel dosimetry, calibration, absorbed dose, uncertainty, zero diffusion
Research Division:Physical Sciences
Research Group:Other Physical Sciences
Research Field:Medical Physics
Objective Division:Health
Objective Group:Other Health
Objective Field:Health not elsewhere classified
Author:Baldock, C (Professor Clive Baldock)
ID Code:97549
Year Published:2013
Deposited By:Office of the School of Engineering
Deposited On:2014-12-22
Last Modified:2015-04-22
Downloads:0

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