凝胶剂量计调强放射治疗三维剂量验证初探

摘要

调强放射治疗(IMRT)是最先进的放射治疗技术之一,因其复杂性和三维治疗计划系统的逆向计算的优化算法在某些方面还不够成熟,所以治疗前必须进行剂量验证以确保治疗剂量的准确性.本文使用聚合物凝胶剂量计对调强放射治疗三维剂量的验证进行初步探索.用丙烯酰胺、明胶、交联剂、除氧剂在常氧条件下制备凝胶剂量计,使用调强放射治疗计划对球形烧瓶(模拟辐照体模)进行辐照,60Coγ射线对同批次制备的剂量计试管进行剂量刻度.其后进行磁共振成像得到刻度曲线和模拟靶区的二维、三维剂量分布.结果表明,新型的凝胶剂量计对剂量的响应能够准确地呈现出靶区形状和三维剂量分布,高剂量梯度区分辨明显.%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 3 D 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 y -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.