A robotic C-arm fluoroscope.

Fluoroscopic C-arms are common devices for acquiring images during surgery. Manual positioning is time consuming and requires considerable experience. Trained users must often take several images to find the best viewing direction. If a second image must be taken from the same position, e.g. for postoperative control, the C-arm must be moved to the exact same position. Without guidance, this is often difficult to accomplish. We developed the idea to completely "robotize" a standard C-arm, i.e. to equip all joints with motors and encoders. A software environment provides for intelligent control. To archive this goal a complete kinematic analysis of the fluoroscope was necessary. On the basis of this analysis a number of clinical applications have been developed: (1) simplified positioning via cartesian control; (2) automatic acquisition of panoramic images; (3) 3D CT with arbitrary viewing angles; (4) 4D intraoperative CT with/without respiration triggering; (5) automated anatomy-oriented positioning. The goal of this research is thus three-fold: minimise radiation exposure of the OR staff, reduce positioning time and offer enhanced imaging capability.