關鍵字: 3D C-arm、C-arm手術導引、脊椎手術 ;Pedicle screws implantation is a high-risk surgery. During operation, the surgeon has to take a lot of C-arm X-Ray images to check if the pedicle screw is in the right path. The medical persons and patient are thus facing a risk of high radiation exposure. This study uses 3D and 2D X-ray images provided by a 3D C-arm to develop a 2D/3D C-arm image assisted surgical navigation system. The 2D system uses only two C-arm images and thus is able to reduce radiation exposure while 3D system is able to provide axial view of the spine for precise path planning. 2D or 3D system leads to more accurate, safe, and efficient surgery . Instead of using the existing double-deck image calibrator, the 2D system applies a free-movable X-Board and a single-deck image calibrator to determine the focus point of C-arm X-ray. The approach can reduce the interference of surgical space and improves positioning accuracy of the system using double-deck image calibrator. The 3D system is able to automatically register 3D images and the patient through a registration board. The system provides a friendly user interface for the surgeon to plan surgical paths on the computer displayed axial, sagittal, and coronal views or on the patient by using a positioning tool. As the results of positioning experiments of 2D system, it is suggested to place the X-Board far away from the C-arm image receiver to obtain precise C-arm projection model and thus to improve positioning accuracy of the system. The average positioning error of single target point is 0.49 ± 0.2mm. On the other hand, the results of the positioning experiment of the3D system show that the positioning error is proportional to the distance between the target and registration board. When the distance reaches 11 cm, the maximum positioning error of system is 1.78mm, however, it is still less the expected 2mm required for clinic application. Key Word : 3D C-arm、surgical navigation system、spine surgery