Abstract：Objective To study the ExacTrac X-ray image guide system for patients with head and neck cancer. Methods Ten patients were chosen foe this study. It was immoblized using the head mask and frame fixtures. The two KV X-ray units were matched with the digitally reconstructed radiographs after positioning with the infrared markers.Then the setup errors on x (horizontal axis),y (vertical axis) and z (up-down) directions and rotation errors were obtained.Paired t-test between any two direction difference errors. Results The setup errors with ExacTrac X-ray image guide system for the patients in x,y,z directions and rotation errors were (0.57±0.24) mm,(0.68±0.19) mm,(1.54±0.29) mm,(0.54±0.13)°,(0.60±0.23)°,(0.51±0.15)°.The z-axis direction have slightly larger error (P=0.02,0.01).The others have not statistical significance (P=0.06,0.10－0.41). Conclusions To use ExacTrac X-ray image guide system cooperating with the six degree of freedom treatment couch in image guided radiotherapy for is feasible, the motion errors<2 mm,the rotation errors<2°.Reduced of the setup errors with replace the sphere or to reduce pollution of the sphere, improve the accuracy,it could provide a better quality assurance in radiation therapy.
Ying Wei,He Youan,He Yong et al. The application of ExacTrac X-ray image guide system for the therapy of head tumor and quality control[J]. Chinese Journal of Radiation Oncology, 2015, 24(2): 193-195.
2015, Vol. 24 
