The thermal measurement by the normoxic methacrylic acid gel had been irradiated radiation

Purpose: In studying normoxic polymer gel dosimeters development, researchers have shown the influence of the temperature history during storage of the gel dosimeter on the dose response curve for two gel dosimeters using the acrylamide based gel dosimeter (nPAG) and methacrylic acid (nMAG). It was found that the methacrylic acid based gel dosimeter is more heat-sensitive than the acrylamide based gel dosimeter upon cooling. The purpose of this study was to fabricate a normoxic methacrylic acid based gel dosimeter that could be used as a thermal dosimeter which is proportional to the temperature in the tissue surrounding lesions of typical thermal therapy. Methods: Thermal dosimetry aims to quantify heat-induced tissue damage based on knowledge of the tissue's temperature profile. This quantitative framework is particularly useful for assessing the biological effects of hyperthermia cancer treatments in clinically-relevant terms. We approach a new way that using the gel dosimeter to evaluate the thermal response. The thermal response of these gels was often investigated by a technique based on magnetic resonance imaging. MRI was undertaken approximately 24 hour after the heating. Results: The thermal response of the current methacrylic acid based gel was haracterized over 22 - 60°C using MRI measurements. The results showed that R^2 values were higher than 0.9885 and the performance were also consistent at radiation dose greater than 15Gy. Conclusion: The experiment established that nMAG gel dosimeters have a good linear response for thermal change ranging from 22-60°C after radiation. We consider that 10-15Gy of radiation dose is a better choice to irritate because excessive dose causes the warming phenomenon on the gel.