Hyper Arc,Dose Comparison of Non-coplanar VMAT and Coplanar VMAT in Stereotactic Radiotherapy for Brain Oligometastases
WANG Tao
LIU Xiaonan
CHENG Xiuyan
MAO Ronghu
GUO Yuexin
Abstract：Objective The dosimetric characteristics of HyperArc technology,volumetric modular arc therapy(VMAT)technology,and coplanar VMAT technology in stereotactic radiotherapy for brain oligometastases were compared,and the potential application of HyperArc technology in this treatment field was explored.Methods A retrospective study was conducted on 10 patients from May 2022 to January 2024 in the First Affiliated Hospital of Zhengzhou University with brain metastases undergoing radiotherapy,prescription dose is 30 Gy in 5 fractions.Treatment plans were designed using hyperarc technology,manual non-coplanar VMAT,and coplanar VMAT,respectively.The RTOG conformity index(CI),Paddick CI,and gradient index(GI)of the PTV(planning target volume)were compared under the three optimization techniques,as well as the V23Gy and V10Gy of the normal brain tissue outside the target area.Results Compared to non-coplanar VMAT technology and coplanar VMAT technology,the Hyperarc technique has shown better dosimetric advantages.The RTOG CI,Paddick CI,and GI parameters for Hyperarc were 1.045±0.033,0.493±0.022,and 3.218±0.954,respectively.The differences in RTOG CI and Paddick CI were statistically significant(P=0.031 9 and P=0.038 7).After removing outliers,the GI for Hyperarc plans was 2.932±0.323,with a statistically significant difference(P＜0.001).In terms of normal brain tissue sparing,compared to non-coplanar VMAT technology,Hyperarc technology had volume deviations of-0.811±0.865 for V23Gy and-3.253±4.028 for V10Gy in normal brain tissue(P=0.016 and P=0.031).Compared to coplanar VMAT technology,Hyperarc technology had volume deviations of(-5.560±3.935)cc for V23Gy and(-69.519±75.094)cc for V10Gy in normal brain tissue(P=0.002 and P=0.017).Conclusion Compared to non-coplanar VMAT and coplanar VMAT,hyperarc technology has better target conformality indices,a better gradient of dose fall-off outside the target area,and a smaller irradiated volume of normal brain tissue.Hyperarc technology is a safe and efficient treatment method for brain metastases.
Keywords：brain metastasesstereotactic radiosurgerystereotactic radiotherapyvolumetric modulated arc therapy
Publication Date：2025-05-13
Online Publishing Date：2026-09-12(First online date of this platform, not the publication date of the document)
Pages：7( 1562-1568 )