Motion-Based Robotic Instrument Targeting under C-Arm Fluoroscopy

We present a simple and precise robot targeting method under portable x-ray fluoroscopy based on image servoing. The method is implemented for needle alignment in percutaneous procedures using the PAKY-RCM robot developed in our laboratory. Initial clinical tests apply to the access of the renal collecting system.Previously reported methods for computer assisted instrument targeting under fluoroscopy use complex robot-image registration algorithms. These approaches use static images of fiducial markers to estimate the robot-image coordinate mapping, which is then used for targeting. In contrast, we report a new method to directly perform targeting by using a marker located on the robot/end-effector and performing fluoro-servoing under continuous imaging. Three-dimensional targeting is achieved by performing the alignment in two dissimilar views acquired at arbitrary C-Arm orientations.The percutaneous access implementation of this method provides automated alignment of the needle towards a surgeon specified target. Needle insertion is then controlled by the surgeon using side-view fluoroscopic feedback.The proposed method offers increased accuracy, simplicity, and repeatability. Moreover, initial clinical experiments suggest that through the use of this method access time and radiation dose have been reduced as compared to normal manual procedures.