Monaco 5.11容积旋转调强中单野单弧与单野双弧的剂量学比较

Single-arc-per-beam and Double-arc-per-beam VMAT Dosimetric Comparison in Monaco 5.11 Treatment Planning System

目的评估Monaco 5.11治疗计划系统"最大每野弧数(Max Number of Arcs)"这一优化参数在制定宫颈癌容积旋转调强计划时对靶区和危及器官的剂量学影响.方法选取20例宫颈癌术后患者,用Monaco 5.11计划系统采用容积旋转调强技术分别制作单野单弧计划(最大每野弧数设置为1)和单野双弧计划(最大每野弧数设置为2),比较两者的靶区剂量、适形度指数、均匀性指数、危及器官受量和机器跳数.结果单野双弧计划的靶区适形度指数和均匀性指数均优于单野单弧计划,差异有统计学意义(P<0.05).膀胱、直肠的平均剂量和左右股骨头的V40差异有统计学意义(P<0.05),其他指标差异无统计学意义.结论单野双弧计划相比于单野单弧计划可以增加靶区的均匀性和适形度,并且可以更好地保护正常组织,在制定宫颈癌容积旋转调强治疗计划时,推荐选择单野双弧计划.

Objective To evaluate the dosimetric effects of the optimization parameter"Max Number of Arcs"of Monaco 5.11 treatment planning system on the target and organs at risk in cervical cancer volumetric modulated arc therapy(VMAT)plan.Methods 20 cases of postoperative patients with cervical cancer were selected,generate two plans on Monaco 5.11 system,one is single-arc-per-beam plan(maximum number of arcs set to 1)and another is double-arc-per-beam plan(maximum number of acrs set to 2)to compare the two plans in target dose,conformity index(Cl),homogeneity index(HI),organs-at-risk(OAR)dose and monitor units(MU).Results Double-arc-per-beam plan is better than single-arc-per-beam plan in HI and Cl(P<0.05).The mean dose of bladder and rectum and V40 of the left and right femoral head are statistically significant(P<0.05),while the other indexes are not significantly different.Conclusion Compared with single-arc-per-beam plan,double-arc-perbeam plan has better homogeneity and confonnity of target,and can better protect normal tissues.Double-arc-perbeam plan is suggested in VMAT plan for cervical cancer.