Effects of collimator angle error on Gamma passing rates for volumetric modulated arc therapy plan for intracranial metastases(PDF)
《中国医学物理学杂志》[ISSN:1005-202X/CN:44-1351/R]
- Issue:
- 2019年第12期
- Page:
- 1411-1415
- Research Field:
- 医学放射物理
- Publishing date:
Info
- Title:
- Effects of collimator angle error on Gamma passing rates for volumetric modulated arc therapy plan for intracranial metastases
- Author(s):
- DENG Guanhua1; HUANG Aihua2; CHEN Lixia3; LUO Longhui1; DAI Peng1; ZHANG Ping1; LAI Mingyao1; SHAN Changguo1; HUANG Qing1; CAI Linbo1
- 1. Department of Oncology, Guangdong Sanjiu Brain Hospital, Guangzhou 510510, China; 2. Department of Respiratory Medicine, Clifford Hospital, Guangzhou University of Chinese Medicine, Guangzhou 511495, China; 3. School of Biomedical Engineering, Southern Medical University, Guangzhou 510515, China
- Keywords:
- Keywords: collimator; angle error; intracranial metastasis; volumetric modulated arc therapy; Gamma passing rate
- PACS:
- R815
- DOI:
- DOI:10.3969/j.issn.1005-202X.2019.12.009
- Abstract:
- Abstract: Objective To analyze the effect of collimator angle error which was simulated by rotating collimator angles on Gamma passing rates for volumetric modulated arc therapy (VMAT) plan for monocentric and multiple intracranial metastases. Methods The non-coplanar VMAT treatment plans of 21 patients with multiple intracranial metastases were analyzed. The radiotherapy plan without collimator angle error was taken as template plan, and then simulation plans were created by recalculating dose profiles without flux optimization after the collimator was rotated by ±0.5°, ±1.0°, ±1.5° and ±2.0°. OmniPro-I’mRT software was used to compare the Gamma passing rates between the template plan and simulation plans under the criteria of 3%/3 mm, 2%/3 mm, 3%/2 mm, 2%/2 mm and 1%/1 mm. The differences in Gamma passing rates of different collimator angles were analyzed by non-parametric paired Wilcoxon rank test. Results Under the criteria of 3%/3 mm, 2%/3 mm, 3%/2 mm, 2%/2 mm and 1%/1 mm, there was statistical difference (P<0.05) in Gamma passing rates when the collimator angle error was greater than 0.5°. The plans with the collimator angle errors of -2.0°, -1.5°, -1.0°, -0.5°, 0.5°, 1.0°, 1.5° and 2.0° had the mean Gamma passing rates decreased by 4.80%, 3.30%, 2.00%, 0.82%, 0.73%, 1.50%, 2.10% and 3.10%, respectively (P=0.003, 0.005, 0.020, 0.593, 0.469, 0.043, 0.030, 0.001), under the criterion of 1%/1 mm. Conclusion With greater collimator angle errors and stricter criteria, the decrease in mean Gamma passing rate becomes larger. The strengthening of quality control and assurance on collimator angle is required to guarantee the accuracy of VMAT delivery and it is recommended that the collimator angle error should be controlled within ±0.5°.
Last Update: 2019-12-24