局部晚期胰腺癌容积旋转调强与五野调强放疗的剂量学比较

摘要

Objective:To explore the dose distribution characteristics between RapidArc and five-field intensity modulated radiotherapy(5F-IMRT) plans in the treatment of locally advanced pancreatic carcinoma,and to provide reference for selecting the appropriate radiation technique in clinic.Methods:Ten patients with locally advanced pancreatic carcinoma were selected.The patients were scanned by simulation CT, and the targets and organs at risk were contoured. RapidArc plan and 5F-IMRT plan were designed respectively.The treatment time and the differences of dose distribution in the targets and organs at risk of RapidArc and 5F-IMRT plans were compared.Results:The conformal index (CI) of RapidArc plan was superior than that of 5F-IMRT plan(P=0.01).The homogeneity index (HI) of targets were similar between two plans (P>0.05).RapidArc plan decreased the maximum dose (Dmax) of the spinal cord(P=0.005);RapidArc plan decreased the mean dose(Dmean) of stomach(P=0.019);5F-IMRT plan decreased the V20 of kidney(P=0.043);RapidArc plan decreased the mean dose(Dmean) of small intestine(P=0.011).The small intestine V10 and V20 of RapidArc plan were lower than those of 5F-IMRT plan(P=0.015,P=0.14);the monitor unit (MU) of RapidArc plan was significantly lower than that of 5F-IMRT plan,with a 18% reduction from the MU level of the latter one,and the treatment time was reduced by 70.3%.RapidArc plan had the smaller doses at liver and kidney compared with 5F-IM RT plan.Conclusion:For the patients with locally advanced pancreatic carcinoma,RapidArc plan has higher CI. RapidArc plan shows the advantages in the protection of organs.Compared with 5F-IMRT,RapidArc plan has less treatment time and significantly improves the curative efficiency.In clinic, the RapidArc plan is recommended.%目的:探讨容积旋转调强放射治疗(RapidArc)与五野调强放射治疗(5F-IMRT)在局部晚期胰腺癌治疗中剂量分布特点,为临床选择合适的照射技术提供参考. 方法:选择局部晚期胰腺癌患者10例,行CT模拟定位,并勾画靶区及危及器官.分别对每例患者设计RapidArc计划和5F-IMRT计划,评估靶区及危及器官的剂量学差异. 结果:RapidArc计划的靶区适形指数(CI)优于5F-IMRT计划(P=0.01),其靶区均匀性指数(HI)比较差异无统计学意义(P>0.05);RapidArc计划中脊髓最大剂量(Dmax)低于5F-IMRT计划(P=0.005);RapidArc计划中胃平均剂量(Dmean)低于5F-IMRT计划(P=0.019);5F-IMRT计划中肾脏V20低于RapidArc计划(P=0.043);RapidArc计划中小肠平均剂量(Dmean)低于5F-IMRT计划(P=0.011);RapidArc计划中小肠V10低于5F-IMRT计划(P=0.015);RapidArc计划中小肠V20低于5F-IMRT计划(P=0.14);RapidArc计划较5F-IMRT计划的平均机器跳数(MU)减少了18.0%,治疗时间缩短了70.3%.RapidArc计划肝脏和肾脏等危及器官受量接近或略小于5F-IMRT计划.结论:RapidArc计划的主要优势为靶区适形度高,可减少MU和缩短治疗时间,能更好地降低危及器官受量.临床上建议设计RapidArc计划.