Abstract

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Title:: Comparison of volumetric modulated arc therapy stereotactic radiosurgery plans of multiple brain metastases

Author(s):: CHEN Zhiran1; WANG Xiaohong2; LI Xiangbin2; MA Pingping3; WEI Wei2; QUAN Hong1; DING Yi2; 1. School of Physics and Technology, Wuhan University, Wuhan 430072, China 2. Department of Radiotherapy, Hubei Cancer Hospital Affiliated to Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430070, China 3. School of Nuclear Science and Technology, University of South China, Hengyang 421001, China

Keywords:: Keywords: brain metastases volumetric modulated arc therapy isocenter stereotactic radiosurgery non-coplanar

Abstract:: Abstract: Objective To study the dosimetric characteristics of volumetric modulated arc therapy (VMAT) in the treatment of multiple brain metastases by adjusting the number of isocenters with coplanar arcs or not. Methods A case of multiple brain metastases treated in Hubei Cancer Hospital in 2019 was selected in the study. Three kinds of plans, namely single-isocenter with 4 non-coplanar arcs, 5-isocenter with 5 coplanar arcs and 5-isocenter with 5 non-coplanar arcs, were designed separately. The prescription dose (24 Gy/3 fractions) was required to cover 95% of the target volume. The evaluation parameters included target conformity index, gradient index, brain radiation necrosis index (V12) and low-dose volume coverage (V5). Results Compared with multi-isocenter plans, VMAT single-isocenter with non-coplanar arcs plan had better target conformity and smaller V12, and it had better dose falloff in the treatment for small-sized tumors. Conclusion VMAT single isocenter with non coplanar arcs plan is more suitable for multiple brain metastases than multi-isocenter plan (coplanar or non-coplanar).