A robust electromagnetic tracking system for clinical applications

Electromagnetic tracking systems (EMTS) are utilized to track surgical instruments during navigated interventions. Compared to optical tracking technologies, the non-line-of-sight feature is the biggest advantage of EMTS. However, significant distortions due to nearby metallic objects and a small working volume are serious drawbacks preventing ETMS from being widely used. We worked on developing new methods to improve the accuracy of EMTS even in the vicinity of large metal objects while speeding up the position estimation frame rate. Therefore, we proposed a method to realize frequency deviation multiplexing (FDM) for EMTS in order to speed up the frame rate, and a quadratic-rectangular (QR) excitation method to remove the distorted voltage induced by the nearby conductive distorter. The results show that the measurement speed and robustness to nearby metal objects of our EMTS were improved by the FDM and QR method. Keyword: Electromagnetic Tracking, Image-guided Interventions, Navigation