Comparative study of incremental dosimetry of HSRT on target area of large volume brain metastases between IMRT and VMAT
10.3969/j.issn.1672-8270.2025.04.002
- VernacularTitle:调强放射治疗与容积旋转调强治疗大体积脑转移瘤分次立体定向放射治疗靶区增量剂量学对比研究
- Author:
Haipeng LYU
1
;
Xiao LIU
;
Jiawei CHEN
;
Mingming SHI
;
Hongyan XU
;
Xiaowei HOU
;
Chuanbin XIE
Author Information
1. 中国人民解放军海军第九七一医院肿瘤科放疗病区 青岛 266000
- Publication Type:Journal Article
- Keywords:
Brain metastases(BMs);
Volumetric modulated arc therapy(VMAT);
Intensity-modulated radiation therapy(IMRT);
Hypofractionated stereotactic radiotherapy(HSRT)
- From:
China Medical Equipment
2025;22(4):6-12
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To compare the dosimetric parameters under different incremental modes between intensity-modulated radiation therapy(IMRT)and volume rotation intensity-modulated therapy(VMAT)for the target area of large volume brain metastases(BMs),and to explore the better way of treating BMs based on hypofractionated stereotactic radiotherapy(HSRT)of linear accelerator.Methods:A total of 30 BMs patients who underwent IMRT at The 971th Hospital of Navy of the CPLA from 2020 to 2023 were selected.In the treatment planning system(TPS),three types of IMRT plans and VMAT plans were designed,which included uniformity plan(Planuniformity)of target area dose,uniform increased plan(Planuniform increased-dose)and incremental plan(Planincremental)within target area.In the inside of the target area,the target area of high dose(GTVh)was set,and Planuniform increased-dose and Planincremental were designed to aim at GTVh.The differences of the doses of three types of treatment plans included Planuniformity,Planuniform increased-dose and Planincremental,which were respectively designed by using IMRT and VMAT,were analyzed.The mean dose(Dmean)of the target area,the 50%and 2%exposed doses(D50%and D2%)of the target area were observed and compared.The conformity index(CI),homogeneity index(HI),gradient index(GI),and the volume percentage(V10 Gy-V40 Gy)that normal brain tissue received 10 Gy-40 Gy also were observed and compared.Results:Compared with Planuniformity of IMRT,the Dmean of GTV of Planuniform increased-dose and Planincremental of IMRT increased by 10.13%and 17.9%,with statistically significant differences(t=13.680,12.771,P＜0.05).D50%increased by 8.9%and 10.8%,with statistically significant differences(t=15.190,9.929,P＜0.05).D2%increased by 15.2%and 46.4%,with statistically significant differences(t=52.320,8.746,P＜0.05).There were no statistically significant differences in normal brain tissue V10 Gy-V40 Gy among Planuniformity,Planuniform increased-dose and Planincremental of IMRT(P＞0.05).Compared with Planuniformity of VMAT,the Dmean of GTV of Planuniform increased-dose and Planincremental of VMAT increased by 10.53%and 21.23%,with statistically significant differences(t=18.641,15.461,P＜0.05),and D50%increased by 9.1%and 13.4%,with statistically significant differences(t=11.382,10.952,P＜0.05),and D2%increased by 16.4%and 48.8%,with statistically significant differences(t=56.471,8.685,P＜0.05),respectively.There were no statistically significant differences in normal brain tissue V10 Gy-V40 Gy among Planuniformity,Planuniform increased-dose and Planincremental of VMAT(P＞0.05).The normal brain tissue V20 Gy,V30 Gy and V40 Gy of Planuniform increased-dose and Planincremental of IMRT were respectively less than those of VMAT,and the differences of them between IMRT and VMAT were significant(tPlan uniform increased-dose=2.112,2.215,2.444,tPlan incremental=2.323,2.939,3.145,P＜0.05).There were no statistically significant difference in D2%,Dmean,and D50%between IMRT and VMAT(P＞0.05).Conclusion:On the premise of ensuring the safety of normal brain tissue at the edge of the target area,the synchronously increasing of the central dose of the target area will not significantly increase the dose for normal brain tissue.Both IMRT and VMAT can meet the requirements of increment in the inside of the target area,and VMAT has slightly better increment and higher efficiency within target area.The incremental of VMAT target area is slightly better,which also has better efficiency,while the enhancement effect of the dose of target area of Planincremental is better than that of the Planuniform increased-dose.The Plan incremental of VMAT is more suitable for HSRT treatment for BMs.
