Characterization of PVA-GTA Fricke gels dosimeters using MRI and optical techniques in X-rays external radiation therapy

The purpose of this work is to study the dependence of the dosimetric properties of poly(vinyl-alcohol)-glutaraldehyde Fricke gel dosimeters (PVA-GTA-FG) both on the irradiation temperature and on temperature changes possibly occurring between the irradiation and readout phases. Such effects were investigated by means of MRI and optical absorbance measurements. The results did not reveal any significant dependence of the sensitivity of the dosimeters on the irradiation temperature in the investigated interval (20◦C-35◦C). In contrast, the effect of the holding temperature may be not negligible. Additionally, PVA-GTA-FG proved to be nearly tissue-equivalent and characterized by a response independent on the energies and dose-rates in the investigated intervals (0-15 Gy). These findings suggested that PVA-GTA-FG are promising tools for clinical dosimetry.