The application of ExacTrac X-ray image guide system for the therapy of head tumor and quality control / 中华放射肿瘤学杂志

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.