Navigated interventions in the head and neck area: standardized assessment of a new handy field generator

Abstract: Electromagnetic (EM) tracking enables localization of surgical instruments within the magnetic field emitted by an EM field generator (FG). Usually, the larger a FG is, the larger its tracking volume is. However, the company NDI (Northern Digital Inc., Waterloo, ON, Canada) recently introduced the Planar 10-11 FG, which combines a compact construction (97mm x 112mm x 31mm) with a relatively large, cylindrical tracking volume (diameter: 340mm, height: 340mm). Using the standardized assessment protocol of Hummel et al., the FG was tested with regard to its tracking accuracy and to its robustness with respect to external sources of disturbance. The mean positional error (5cm distance metric according to Hummel protocol) was 0.59mm, with a mean jitter of 0.26mm in the standard setup. The mean orientational error was found to be 0.10{\deg}. The highest positional error (4.82mm) due to metallic sources of disturbance was caused by the steel SST 303. In contrast, steel SST 416 caused the lowest positional error (0.10mm). Overall, the Planar 10-11 FG tends to achieve better tracking accuracy results compared to other NDI FGs. Due to its compact construction and portability, the FG could contribute to increased clinical use of EM tracking systems.