Abstract：Objective To verify the clinical feasibility of Exactrac 2D image guidance system for brain tumor SRS non-coplanar
arc treatment, the accuracy of positioning error detection and error correction ability of Exactrac 2D image guidance system were
tested using Varian 3D OBI image guidance system. Methods Twenty-eight patients with brain metastases were selected. The iPlan
system was used for SRS non-coplanar arc treatment. The Exactrac 2D image guide system was used to get the 6D positioning error.
After automatic registration, the 6D couch was used to correct the positioning error. When the final positioning finished, the image
was scanned with Exactrac System and Varian OBI system to calculate and analyze the positioning error. Results Twenty-eight
patients underwent a total of 256 image guided scans. Exactrac system before the correct translation error standard deviation of X,
Y, Z direction were: （1.73±1.61）,（0.68±2.88）,（-1.45±3.83）mm. The three axis rotation error of the standard deviation
were: -1.26°±1.34°,-0.17°±0.65°,0.37°±0.66°. After Exactrac system combined with 6D couch to correct, the images scanned
by Exactrac and OBI showed the translation error can be controlled within 1 mm, and the angle error can be controlled within 0.5°.
Conclusion Two dimensional Exactrac position verification system can meet the clinical requirement of SRS for brain tumor.
赵利荣，周一兵，孙建国. Exactrac系统在SRS非共面放疗中位置验证的可行性研究[J]. 中国医疗设备, 2021, 36(8): 35-39.
ZHAO Lirong, ZHOU Yibing, SUN Jianguo. Feasibility Study of Exactrac System for Location Validation in Non-coplanar SRS Radiotherapy. China Medical Devices, 2021, 36(8): 35-39.
