摘要
目的:比较不同等中心定义方式对高级别脑胶质瘤(HGG)术后容积弧形调强放射治疗(VMAT)计划的影响,探讨在CT模拟系统(CT-Sim)定位阶段确定治疗等中心的可行性。方法:回顾性选取2021年9月1日至2022年12月31日在北京大学国际医院就诊的30例HGG术后放疗患者,每例患者分别使用CT-Sim定位阶段勾画瘤床靶区的质心(CT-COM)、治疗计划系统(TPS)中计划靶区的几何中心(TPS-Geo)、TPS中全脑几何中心(TPS-Head)和TPS中计划靶区的质心(TPS-COM)4种方式定义治疗等中心,分别设置为CT-COM、TPS-Geo、TPS-Head和TPS-COM,设计VMAT的4种计划,对4种计划靶区及危机器官(OAR)剂量、适形指数(CI)、均匀指数(HI)、机器跳数等参数进行比较。结果:4种计划靶区和OAR剂量相近,均能满足临床剂量学和临床OAR剂量限值要求,差异无统计学意义(P>0.05)。CT-COM、TPS-Geo、TPS-COM的3种计划脑组织受到10、20、30、40和50 Gy剂量覆盖的体积(V_(10)、V_(20)、V_(30)、V_(40)、V_(50))与脑干、双侧晶状体、视交叉、双侧视神经、垂体的最大剂量、2%体积接受的最大剂量、平均剂量(Dmax、D2%、Dmean)接近,TPS-Head组计划的脑组织V10、V20、V30和脑干Dmax、D2%、Dmean略高于其他3组,健侧晶状体D_(mean)与健侧视神经D_(max)、D2、D_(mean)略低于其他3组,差异无统计学意义(P>0.05)。结论:4种定义治疗等中心的VMAT计划均能满足临床剂量学要求,且在CT-Sim定位阶段确定等中心,能够有效避免放疗复位过程中产生的误差,提高放疗剂量传递精度,提升设备的有效利用率。
Objective:To compare the influence of definition methods of different isocenter on postoperative volumetric modulated arc therapy(VMAT)plans for patients with high-grade glioma(HGG),and to explore the feasibility of determining the treatment isocenter at location stage of computed tomography(CT)simulation system(CT-Sim).Methods:A total of 30 HGG patients who received radiotherapy after surgery in Peking University International Hospital from September 1,2021 to December 31,2022 were selected.4 kinds of methods,which included center of mass(CT-COM)of target region of tumor bed was delineated by CT-Sim location stage,geometric center of target region of treatment plan system(TPS-Geo),whole brain geometric center of treatment plan system(TPS-Head)and center of mass of target region of TPS(TPS-COM),were respectively adopted to definite treatment isocenter for each patient,and they were respectively set as CT-COM group,TPS-Geo group,TPS-Head group and TPS-COM group to design 4 groups of VMAT treatment.The parameters included dose,conformity index(CI),uniformity index(HI)and machine unite(MU)among 4 groups of target region and organ at risk(OAR)were compared.Results:The doses of target region and OAR of four groups were similar,and all of them can meet the requirements of clinical dosimetry and clinical OAR dose limitation,without statistically significant differences(P>0.05).The covered volumes that brain tissues received 10,20,30,40 and 50 Gy doses in CT-COM group,TPS-Geo group and TPS-COM group closed to the maximum dose,the maximum dose of 2%volume and mean dose(D_(max),D2%,D_(mean))of brainstem,bilateral lens,optic chiasm,bilateral optic nerve and pituitary gland.The V_(10),V_(20),V_(30) of brain tissue,and Dmax,D2%,and Dmean of brainstem in TPS-Head group were slightly higher than those in other three groups,and the Dmean of lens,and Dmax,D2%and Dmean of optic nerve at health side of TPS-Head group were slightly lower than those of other three groups,without statistically significant differences(P>0.05).Conclusion:The four VMAT plans of defining the treatment isocenter can meet the clinical dosimetric requirements,and can determine the isocenter at CT-Sim location stage,which can effectively avoid the occurrence of errors in the reduction of radiotherapy,and increase precision of delivery of radiotherapy dose,and enhance effective utilization rate of equipment.
作者
孙博
陈星宇
刘芳
庞得全
吴青南
杨雨岩
王济东
Sun Bo;Chen Xingyu;Liu Fang;Pang Dequan;Wu Qingnan;Yang Yuyan;Wang Jidong(Department of Radiotherapy,Peking University International Hospital,Beijing 102206,China;Shandong Medical College,Jinan 250002,China;Department of Radiotherapy,Affiliated Hospital of North China University of Science and Technology,Tangshan 063000,China)
出处
《中国医学装备》
2025年第1期7-12,共6页
China Medical Equipment
