Clinical acceptance tests of an optical surface imaging (OSI) system
10.3760/cma.j.cn112271-20240509-00170
- VernacularTitle:光学表面成像系统临床应用的验收测试
- Author:
Zhen ZHOU
1
;
Bei WANG
1
;
Tingting DONG
1
;
Fei JIANG
1
;
Feiyu ZHU
1
;
Bo YANG
1
;
Jie QIU
1
Author Information
1. 中国医学科学院北京协和医院放射治疗科，北京 100730
- Publication Type:Journal Article
- Keywords:
Optical surface imaging;
Acceptance test;
Gating system;
Dosimetric difference
- From:
Chinese Journal of Radiological Medicine and Protection
2024;44(12):1013-1019
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To perform clinical acceptance tests of an optical surface imaging (OSI) system to ensure its accuracy and reliability in clinical applications.Methods:Based on the AAPM TG147 and AAPM TG302 reports, clinical tests were conducted for various performance indicators of the AlignRT system using phantoms, followed by the quantitative assessment of the system′s overall operational accuracy. Additionally, gating tests were performed on the radiotherapy plans of 13 patients to characterize the overall dosimetric accuracy of gated delivery under the guidance of the AlignRT system.Results:The camera units of the AlignRT system exhibited average relative positional deviations of 0.34 and 0.47 mm, respectively. The positional deviations from the radiation isocenter can be corrected through calibration with a phantom. Thermal drift primarily occurred in the vertical ( y) and longitudinal ( z) directions, measuring 0.2 and 0.3 mm, respectively. The accuracy deviation caused by differences in ambient light intensity was approximately 0.04 mm. When a camera unit was obstructed, the primary deviation was found in the lateral ( x) direction, about 0.15 mm. In the translational direction, the maximum deviation in positioning accuracy was 0.4 mm. During couch rotation, primary deviation occurred in the direction of YAW rotation, averaging 0.38°. There was a strong correlation between system monitoring deviations and cone-beam CT (CBCT) registration deviations, with correlation coefficients exceeding 0.8. In the case of gated delivery, the relative gamma pass rate for dose distribution exceeded 99% compared to the non-gated delivery. Conclusions:The AlignRT system provides sub-millimeter monitoring accuracy, meeting the demand for patient position verification and real-time monitoring in clinical treatment. Given that the introduction of a linear accelerator into gating did not result in significant dosimetric deviations, clinical plans can be performed reliably using gated treatment.
