Study on the influence of definition methods of different isocenter at location stage with CT simulation on the quality of postoperative radiotherapy plan for high-grade gliomas
10.3969/j.issn.1672-8270.2025.01.002
- VernacularTitle:CT模拟定位阶段不同等中心定义方式对高级别脑胶质瘤术后放射治疗计划质量的影响研究
- Author:
Bo SUN
1
;
Xingyu CHEN
;
Fang LIU
;
Dequan PANG
;
Qingnan WU
;
Yuyan YANG
;
Jidong WANG
Author Information
1. 北京大学国际医院放疗科 北京 102206
- Publication Type:Journal Article
- Keywords:
Volumetric modulated arc therapy (VMAT);
High-grade glioma (HGG);
Isocenter;
CT simulation
- From:
China Medical Equipment
2025;22(1):7-12
- CountryChina
- Language:Chinese
-
Abstract:
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 (Dmax,D2％,Dmean) of brainstem,bilateral lens,optic chiasm,bilateral optic nerve and pituitary gland. The V10,V20,V30 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.
