VMAT plan verification based on ArcCHECK phantom and the effects of setup error on dose verification(PDF)
《中国医学物理学杂志》[ISSN:1005-202X/CN:44-1351/R]
- Issue:
- 2020年第4期
- Page:
- 431-438
- Research Field:
- 医学放射物理
- Publishing date:
Info
- Title:
- VMAT plan verification based on ArcCHECK phantom and the effects of setup error on dose verification
- Author(s):
- SHEN Hao; XIA Bing
- Department of Radiotherapy, the First Affiliated Hospital of China Medical University, Shenyang 110001, China
- Keywords:
- Keywords: ArcCHECK; volumetric modulated arc therapy; dose verification; Gamma analysis; DTA analysis; setup error
- PACS:
- R811.1
- DOI:
- DOI:10.3969/j.issn.1005-202X.2020.04.007
- Abstract:
- Abstract: Objective To explore the application of ArcCHECK phantom in volumetric modulated arc therapy (VMAT) plan verification, and to simulate the effects of setup error on dose verification by software. Methods A total of 45 VMAT plans were randomly collected, including 15 cases of chest tumors, 15 cases of breast cancer and 15 cases of cervical cancer. The dose distribution measured by ArcCHECK phantom was compared with the calculated result of planning system for analyzing the passing rates of relative dose (RD) and absolute dose (AD) under Gamma analysis and DTA analysis with the threshold at 10%, 3%/3 mm and 2%/2 mm. The Sunpatient software from SUNnuclear was used to compare the dose distribution calculated by planning system with the measured dose distribution and to simulate rotation errors by rotating ±0.5°, ±1°, ±1.5°, ±2°, respectively. The passing rate of plan verification under rotation errors was obtained by comparing the dose distribution after rotation and the dose distribution calculated by planning system. The software was also used to simulate translation errors. The passing rate of plan verification under translation errors was obtained by comparing the dose distribution after shifting ±1, ±2, ±3, ±5 mm to the X and Y directions, respectively, and the calculated results. Results When the threshold was selected at 10%, 3%/3 mm, the passing rate of RD and AD in VMAT plans for different cancer was basically up to or higher than 95% in Gamma analysis and 90% in DTA analysis. When the threshold was selected at 10%, 2%/2 mm, the average passing rates of RD and AD in VMAT plan for different cancer were only about 80% whether in Gamma analysis or DTA analysis. When the rotation error was greater than or equal to 1°, the one-way ANOVA on the passing rate of VMAT plan verification by two analysis methods showed that the P value was less than 0.05. When the translation errors in X and Y directions were greater than or equal to 3 mm, one-way ANOVA showed that the P values were also less than 0.05. Conclusion ArcCHECK phantom can be well applied to VMAT plan verification. With the threshold at 10%, 3%/3 mm, the passing rate of the verification of VMAT plans for chest tumors, breast cancer and cervical cancer is up to or higher than 95%, but the passing rate is dropped to about 80% when the threshold was set at 10%, 2%/2 mm. The rotation error which is greater than or equal to 1° has a significant effect on the passing rate of plan verification, with statistical differences. When the translation errors in X or Y directions are greater than or equal to 3 mm, there are significant differences in the passing rate of plan verification between two analysis methods.
Last Update: 2020-04-29