直肠癌术后容积旋转调强和静态调强放疗的剂量学研究

Dosimetric Comparison Between RapidArc and IMRT for Postoperative Rectal Cancer

目的:比较直肠癌术后患者瓦里安容积旋转调强(RapidARC)和静态调强(Intensity Modulated Radiotherapy,IMRT)两种调强放疗技术的剂量学差异。方法:应用ADAC Pinnacle V9.2放疗计划系统,对20例直肠癌术后患者分别设计Rapid Arc和IMRT放射治疗计划,处方量统一为50.4 Gy分28次照射,比较这两种治疗计划中靶区和危及器官的剂量学差异,以及这两种计划的机器跳数(MU)和治疗时间。结果:两组治疗计划靶区的Dmean、Dmin、Dmax、Dmean、V95%、CI、HI相近,无统计学意义(P>0.05);膀胱和小肠的V50,小肠Dmax,以及左右股骨头的V50、Dmean两种计划比较差异无统计学意义(P>0.05);Rapid ARC计划的膀胱和小肠的Dmean、总机器跳数和治疗时间明显低于IMRT,差异有统计学意义(P<0.05)。结论 :在直肠癌术后患者的放射治疗中,RapidArc和IMRT放射治疗计划的靶区剂量相近。RapidArc减少了膀胱和小肠的平均剂量、总的MU,缩短了治疗时间。

Objective： To compare the dosimetric difference between RapidArc and IMRT for postoperative rectal cancer. Methods： This retrospective study chosed 20 treated patients of Postoperative Rectal Cancer. All of the patients were redesigned their treatment plans to a unique prescription, 1.8 Gy＊28 f, with both RapidArc and IMRT techniques using ADAC Pinnacle V9. 2 treatment planning system. Dose distribution on target volumes, organs at risks, number of monitor units and treatment delivery time were compared in this study. Results： There were no dosimetic difference between RapidArc and IMRT about the PTV Dmean,Dmax,Dmax,V95%、CI,HI （P〉0.05）. The bladder V50,small bowel V50,Dmax and the femoral head V50, Dmean were similar（P〉0. 05）. But RapidArc significantly reduced the delivered mean dose on both bladder and small bowel, treatment time and monitor units （P〈0.05）.Conclusions： RapidArc plans can meet the clinical therapy needs for Postoperative Rectal Cancer. In this study, plans with RapidArc technique achieve similar PTV dose coverage and reduced the delivered dose on bladder and small bowel as well as treatment time and monitor units compared with which used IMRT technique.