A primary limitation of current x-ray CT polymer gel dosimetry is the low contrast, and hence poor dose resolution, of dose images produced by the system. This study reports on the use of x-ray CT imaging to image a new formulation of radiosensitive polymer gel materials for use in dosimetric verification of radiotherapy cancer treatments. The polymer gel dosimeter formulation (incorporating an isopropanol co-solvent into an N-isopropylacrylamide-based gel) is designed to maximize the sensitivity of the gel to radiation and hence maximize the contrast obtained when the gels are imaged with x-ray CT. Results indicate that the proposed new gel formulation is sensitive, stable and able to improve the dose resolution over current formulations. The polymer gel/x-ray CT system has the potential to be used for 3D dosimetry of radiotherapy treatments.

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