摘要
目的:比较控制点数量对右侧乳腺癌术后容积旋转调强放疗(volumetric modulated arc therapy,VMAT)计划的剂量学影响。方法:选取15例右侧乳腺癌术后患者,利用Monaco 5.1计划系统进行计划靶区(planning target volume,PTV)勾画和计划设计。将控制点数量分别设置为20、30、40、50、60,在同等优化条件下,比较不同控制点计划目标靶区和危及器官的剂量学差异。采用SPSS 22.0软件进行统计学分析。结果:随着控制点数量的增加,靶区的适形性指数逐渐增大(分别为0.59±0.07、0.67±0.06、0.70±0.06、0.71±0.08、0.70±0.08)且差异有统计学意义(P=0.00),均匀性指数也逐渐增大(分别为1.23±0.10、1.11±0.03、1.09±0.02、1.07±0.02、1.08±0.02)且差异具有统计学意义(P=0.00)。当控制点数量低于30时,右肺V5更小但是靶区剂量覆盖较差(P<0.05);当控制点数量设置为50时,目标靶区均匀性指数和适形性指数最优;当控制点数量大于50时,目标靶区适形性指数和均匀性指数开始变差。所有计划危及器官剂量均能达到临床限制要求。结论:设计右侧乳腺癌术后VMAT计划时,单弧最大控制点数量推荐使用50,若临床上对特定患者肺组织低剂量照射区有保护需求,可以选择适当减少控制点数量进行剂量优化。
Objective To explore the dosimetric effects of numbers of control points on planning of volumetric modulated arc therapy(VMAT)for postoperative right-sided breast cancer.Methods Fifteen patients with postoperative right-sided breast cancer were selected and Monaco 5.1 planning system was used for planning target volume(PTV)outlining and plan design.The number of control points was set to 20,30,40,50 and 60,respectively,and the dosimetric differences of the PTV and organs at risk at different control points were compared under the same optimized conditions.SPSS 22.0 software was used for statistical analysis.Results As the number of control points rose,the conformity index of the PTV increased gradually(0.59±0.07,0.67±0.06,0.70±0.06,0.71±0.08 and 0.70±0.08 respectively)with statistically significant differences(P=0.00),the homogeneity index also ascended gradually(1.23±0.10,1.11±0.03,1.09±0.02,1.07±0.02 and 1.08±0.02 respectively)with statistically significant differences(P=0.00).The right lung V5 decreased while the dose to PTV was not satisfactory(P<0.05)when the number was lower than 30,the PTV homogeneity index and conformity index were optimal when the number was set to 50,and the PTV conformity index and homogeneity index got worse when the number was higher than 50.The doses to the PTV and organs at risk all met the clinical requirements.Conclusion When designing VMAT plans for right-sided postope-rative breast cancer radiotherapy,the maximum number of control points in a single arc is recommended to be 50.If there is a clinical need for protection of low-dose irradiated areas of lung tissue in a specific patient,the number of control points has to be reduced properly for dose optimization.
作者
吴晓辉
胡小容
罗桃红
姚祖文
徐珊珊
刘洋
谢堂
刘睿
WU Xiao-hui;HU Xiao-rong;LUO Tao-hong;YAO Zu-wen;XU Shan-shan;LIU Yang;XIE Tang;LIU Rui(Department of Radiation Oncology,Cancer Center of Suining Central Hospital,Suining 629018,Sichuan Province,China;Department of Nutrition,Suining Central Hospital,Suining 629099,Sichuan Province,China)
出处
《医疗卫生装备》
CAS
2023年第3期54-57,共4页
Chinese Medical Equipment Journal
关键词
乳腺癌
控制点数量
VMAT
剂量学
breast cancer
number of control points
VMAT
dosimetry
作者简介
吴晓辉(1993-),男,工程师,主要从事肿瘤放射物理及质控方面的研究工作,E-mail:939604485@qq.com;通信作者:刘睿,E-mail:10686801@qq.com。
