Enhanced Electromagnetic Navigation

Accurate localization of medical instruments with respect to patient anatomy is an integral part of computer-assisted interventions. Electromagnetic (EM) tracking is the primary choice, particularly for minimally invasive procedures subject to visual tracking occlusion. In this case, known local EM fields are generated by transmitters in order to localize EM sensors (trackers) placed within the field, using the principle of mutual induction. This technology has been integrated into various commercial products, and applied in several interventions. This popularity is primarily due to freedom from line-of-sight restrictions, small sensor size, and the ability to track instruments inside the patient’s body, which is particularly helpful for guiding needles, catheters, and guide wires, during insertions.

Unfortunately, EM measurements are susceptible to field distortion caused by magnetic and electrically-conductive objects located in the close proximity of the tracking volume. In a clinical environment, such sources of field distortion include medical imaging devices, equipment, and instruments. Many studies have looked at the static, dynamic, and field distortion errors. In general, the combined tracking error ranges from a few millimeters in research environments to a few centimeters in clinical environments. Unless compensated for, this error compromises the outcome of medical procedures and limits the reliability and utility of EM tracking in clinical settings. This research is aimed to alleviate EM tracking limitations and provide improved tracking performance.