不同体积脑转移瘤对容积旋转调强计划摆位误差的敏感性-《中国医学物理学杂志》

文章信息/Info

Title:: Sensitivity of volumetric modulated arc therapy plan to setup errors in radiotherapy for brain metastases of various sizes

文章编号:: 1005-202X（2024）05-0529-05

作者:: 徐中标; 黄唯; 南方医科大学附属广东省人民医院（广东省医学科学院）放疗科，广东广州 510080

Author(s):: XU Zhongbiao; HUANG Wei; Department of Radiation Oncology, Guangdong Provincial Peoples Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou 510080, China

Keywords:: Keywords: brain metastasis volumetric modulated arc therapy rotational setup error translational setup error sensitivity

分类号:: R739.41；R811.1

DOI:: DOI:10.3969/j.issn.1005-202X.2024.05.001

文献标志码:: A

Abstract:: Abstract: Objective To explore the sensitivity of volumetric modulated arc therapy (VMAT) plan to setup errors in radiotherapy for brain metastases of various sizes. Methods Five spheres were set to simulate multiple brain metastases in the CT image, with the volumes of 0.5, 1.7, 4.0, 8.1, and 14.0 cm3, respectively. A single isocenter 5-arc non-coplanar VMAT plan was generated, and the distance from isocenter to each target was 5 cm. The rotational setup error θ around the Z axis was simulated by rotating the treatment couch (clockwise from -3.0° to 3.0°, with a step length of 0.5°) and the translational setup error (from -3.0 mm to 3.0 mm, with a step length of 0.5 mm) was simulated by changing the position of the isocenter on the three-dimensional axis (X/Y/Z). The dose distribution was recalculated in the optimization conditions remaining unchanged. The target coverage after rotation and translation was recorded and normalized to the relative coverage without setup error. The correlation between the target coverage of brain metastases of various sizes and the setup error was analyzed with linear regression method. Results The relative coverage decreased gradually as rotational setup error increased. With the same rotational setup error, the relative coverage was in linear correlation with target volume (θ=0.5°, P=0.006 θ=1.0°, P=0.024 θ=1.5°, P=0.028 θ=2.0°, P=0.019 θ=2.5°, P=0.014 θ=3.0°, P=0.007), and the relative coverage increased with increasing target volume. When the rotational setup error was less than 0.5°, the relative coverage was less than 2% regardless of whether the target area was large (14.0 cm3) or small (0.5 cm3). The relative coverage decreased gradually as translational setup error increased. Compared with large target area, small target area was more sensitive to translational setup error. When the translational setup error was less than 0.5 mm, the relative coverage of the large target area varied less than 2%, while the relative coverage of the small target area (0.5 cm3) decreased by nearly 5%. Conclusion When the rotational setup error is constant, the relative coverage of the target has linear relationship with target volume. Small target area is more sensitive to translational setup error than large target area. The rotational setup error within 0.5° and the translational setup error within 0.5 mm are recommended when implementing SRS VMAT plan for small target area.

《中国医学物理学杂志》[ISSN:1005-202X/CN:44-1351/R]

文章信息/Info

备注/Memo

常用功能

导航/Navigate

工具/Tools

统计/Statistics