Feasibility study of three-dimensional dose verification for intensity modulated radiation therapy using gel dosimeter

Intensity modulated radiation therapy (IMRT) is one of the most advanced radiation treatment technologies. However, it is complicated and there are many immature aspects in the optimization calculate of three- dimension treatment planning system. Therefore, we have to verify the dosimeter for guaranteeing the accuracy of the dosage before treating. The 3D dose verification of the intensity modulated radiation therapy was studied, using polymers. First, gels were prepared with water, acryl-amide, gelatin, BIS and THPC. Next, global flask (Simulating phantom) was irradiated with intensity modulated radiation therapy, and the test tubes in the same batch are scaled with 60Co γ-rays. Then, the curves of 2D and 3D dose distribution of target region were obtained by nuclear magnetic resonance (NMR). The results show that these new gel dosimeters can accurately present the shape of target region and get the 3D dose distribution, with obvious dose distribution in high gradient regions. (authors)