Accuracy of the optically guided tracking system in radiotherapy
10.3760/cma.j.cn112271-20230412-00116
- VernacularTitle:光学引导跟踪系统在放疗应用中的准确性研究
- Author:
Zhanghua LIN
1
;
Xianzhi DENG
;
Fangfen DONG
;
Jing CHEN
;
Fen ZHENG
;
Xing WENG
;
Benhua XU
;
Xiaobo LI
Author Information
1. 福建医科大学医学影像学院 福建医科大学肿瘤中心 福建省肿瘤智能影像与精准放疗重点实验室 福建省消化、血液系统与乳腺恶性肿瘤放射与治疗临床医学研究中心，福州 350001
- Keywords:
Optically guided tracking system;
Image-guided radiotherapy;
Tracking accuracy;
Setup error
- From:
Chinese Journal of Radiological Medicine and Protection
2023;43(9):698-704
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To explore the tracking accuracy of the surface optically guided tracking system (OGTS) in radiotherapy.Methods:Phantom verification and clinical trial verification were adopted. Specialized equipment was employed for the phantom verification. Specifically, the displacement of the optical markers as they moved from a predetermined position to the target position on the reflector ball platform was captured using the OGTS, and then the obtained displacement was compared with the fixed distance within the phantom to calculate the accuracy and repeatability of the OGTS. For the clinical trial verification, 45 patients treated with radiotherapy, which consisted of 15 cases with head, breast, and rectal tumors each, were selected to investigate the tracking accuracy and repeatability of the OGTS. For each patient, the values derived from the image-guided positioning system (IGPS) and the OGTS before and after image-guided setup error correction during three times of fractionated radiotherapy were randomly obtained. The translational errors of each error correction were also recorded. Before radiotherapy, patients′ setup errors were corrected and relevant data were obtained using the IGPS. The correction result of translation errors obtained using the IGPS served as a gold standard to verify the accuracy of the OGTS in monitoring the translational motion of patients. Finally, the comprehensive translational deviation of both method was calculated.Results:The phantom measurements showed that the comprehensive translational deviation for tracking accuracy and tracking repeatability of the OGTS had a maximum deviation and a standard deviation of 0.18 mm and 0.03 mm, respectively. The clinical trial result indicated that the tracking accuracy of IGPS and OGTS exhibited statistically significant differences only for the head in the z direction ( t = 2.21, P < 0.05). Conversely, no statistically significant differences were observed for the head in the remaining directions or for the breast and rectum in the three translational directions ( P > 0.05). The analysis showed that comprehensive translational deviations for the head, breast, and rectum derived from OGTS and IGPS were (0.91±0.62), (1.64±1.30), and (1.52±1.29) mm, respectively, satisfying the requirement that the deviations should be below 2 mm. Conclusions:The OGTS, featuring easy operation and high tracking accuracy, can assist the IGPS in real-time respiratory monitoring during radiotherapy.
