EVALUATION OF TARGETING FRAMES FOR DEEP-BRAIN STIMULATION USING VIRTUAL TARGETS

Surgery for deep-brain simulation (DBS) requires implanting of stimulators at target positions with submillimetric accuracy, typically via stereotactic frames. A recent innovation replaces the large, universal frame with a miniature frame customized per patient. We present a method for evaluating the accuracy of these new frames using "virtual targets" to avoid collision of implant with target. We implement virtual targets by mounting fiducial markers on an artificial skull and defining the targets relative to that fiducial system. The fiducial system is designed such that it surrounds the targets, thereby reducing the overall effect of fiducial localization inaccuracies. It also provides the transformation from image to physical space. Target selection is based on an atlas of stimulation targets from a set of 31 DBS patients. The measured error is the displacement between phantom implant and virtual target. The new frame was found to have submillimetric accuracy with 0.45 mm RMS error