Position and orientation tracking method of an invasive device by using MRI

The combination of MR guided surgery and computer aided surgery has a potential to ensure accurate, certain, and safe procedures. Although a tracking device is indispensable for computer assisted surgery, conventional tracking devices are not available or difficult to use in a MR scanner because of occlusion and strong magnetic field. We proposed a novel tracking method by using MR scanner. The method provides three dimensional positions and orientations of a miniature receiver coil (tracking coil) consisted of three marker coils and tuning capacitor, and matching capacitor. We describe experiments we conducted to evaluate the basic performance of the method. First, a surgical tool affixed the tracking coil was calibrated. Next, measurement accuracy of the tool's tip position and orientation was evaluated. The error of root mean square was 0.92 mm and 0.47 degree. This paper recommends a tracking method for computer assisted surgery with MRI to enable tracking in MR environment. Results obtained with the method demonstrate its feasibility.