Gel dosimeter
Development of gel dosimeter for high-precision radiation therapy planning
Approximately one in three Japanese have died of cancer, therefore development of cancer treatment technology is the most important issue. Radiation therapy can cure the cancer without cutting, so it maintains the form and function of our body even after healing. In a particular field of advanced radiation therapy, knowing exact spatial dose distribution in vivo is critically important. In our research project, tissue equivalent gel dosimeter is developed using radiation-crosslinked hydroxypropylcellulose (HPC) as a base material to evaluate three-dimensional dose distributions accurately. Polymer gel dosimeter is prepared by irradiating the HPC solution with electron beam to make radiation-crosslinked hydrogel, and immersed it in an aqueous solution of nonaethylene glycol dimethacrylate and 2-hydroxyethyl methacrylate. Although this is transparent gel before irradiation, it becomes cloudy enough to see in the irradiation of about 2 Gy which is an applied dose in radiation therapy. Degree of cloudiness (sensitivity) can be controlled by the composition of the detector reagent.
