On the comparison of the accuracies of optical tracking and EMTS modalities of surgical navigators

The objective of this study was to compare the real-world in-hospital working accuracies of optical tracking and electromagnetic tracking system modalities of surgical navigators that enable the use of both modalities. Two special phantoms for this purpose were designed and developed at the Department of Mechanical Engineering, University of Oulu, and Oulu University Hospital, Oulu, Finland, by the authors of this study. A total of 147 calibration points was collected using each modality and the results were analyzed. The analysis revealed that within a common operating area, there is no appreciable difference in the accuracies of these modalities and that the accuracy of each modality remained within a safe mean operating range of 1.00 mm. Overall, the comparison analysis indicates that the accuracies of these modalities are nearly identical, so the accuracy does not depend on the navigator´s tracking system. This study also shows that the error increase is directly proportional to the distance from the electromagnetic field generator of the EMTS and directly proportional to the distance from the center of the phantom for the optical tracking modality.