A preliminary study on a method for detecting accelerator isocenter deviation using an optical surface monitoring system
10.13491/j.issn.1004-714X.2026.02.017
- VernacularTitle:利用光学表面监测系统检测加速器等中心精度的方法初探
- Author:
Jianqi HU
1
;
Shun ZHOU
2
;
Jiangyan LUO
1
;
Zihong LU
2
;
Junyu LI
2
;
Wen WANG
3
;
Hao WU
4
Author Information
1. Institute of Medical Technology, Peking University Health Science Center, Beijing 100191, China.
2. Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Department of Radiation Oncology, Peking University Cancer Hospital & Institute, Beijing 100142, China.
3. The Second Affiliated Hospital of Guizhou University of Traditional Chinese Medicine, Guiyang 550003, China.
4. Institute of Medical Technology, Peking University Health Science Center, Beijing 100191, China;Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Department of Radiation Oncology, Peking University Cancer Hospital & Institute, Beijing 100142, China.
- Publication Type:OriginalArticles
- Keywords:
Optical surface monitoring system;
Isocenter;
Front pointer;
Quality control
- From:
Chinese Journal of Radiological Health
2026;35(2):263-271
- CountryChina
- Language:Chinese
-
Abstract:
Objective To detect the isocenter of a medical linear accelerator using an optical surface monitoring system (OSMS) combined with a self-made 3D-printed phantom, and compare with the conventional front pointer measurement method. Methods A phantom that could be fixed to the front pointer of the accelerator was fabricated using 3D printing technology. The front pointer method and OSMS were used to detect the rotation isocenter deviations of the accelerator. During the experiments, the collimator, gantry, and couch linear displacement readings were recorded at different angles. We also recorded the measurement time of different surveyors. Results Compared to the front pointer measurement method, the OSMS method showed lower standard deviations. The reductions in standard deviations showed statistical significance in the Lat direction for the collimator rotation isocenter as well as in the Lat and Vrt directions for the gantry rotation isocenter. The mean deviation of Mag values for the collimator rotation isocenter using the OSMS method was 0.50 mm, which was larger than the 0.42 mm using the front pointer method. However, the standard deviation was 0.06 using the OSMS method, which was smaller than the 0.18 using the front pointer method. The mean deviation and standard deviation of Sag values for the gantry rotation isocenter using the OSMS method were 1.03 mm and 0.12, respectively, which were both larger than 0.47 mm and 0.06 using the front pointer method. For the couch rotation isocenter, the mean deviation and standard deviation using the OSMS method were 0.32 mm and 0.04, respectively, which were both smaller than the 0.55 mm and 0.20 using the front pointer method. All surveyors spent less time in isocenter measurements using the OSMS method compared to the front pointer method. Conclusion Compared with the front pointer method, the OSMS method significantly reduces the standard deviation among surveyors, effectively reduces the influence of the angle deviation of the accelerator on the measurement results, reduces detection time, improves detection efficiency, and provides a powerful practical basis for the application of OSMS in detecting the mechanical accuracy of the linear accelerator.
