Evaluation of EM tracking systems for laparoscopic liver surgery

The objective of this paper is to evaluate electromagnetic tracking for laparoscopy with miniature tracking systems: the microBIRD (TM) from Ascension and the AURORA (TM) from NDI Our tests show that the new 6DOF (degree of freedom) sensor from NDI is as good as the established 5DOF sensor. Tests with help of a robot in the operating room showed that the AURORA (TM) system is more disturbed when lying on the OR table than standing aside. Various tools were evaluated if they can be used for laparoscopic surgery. Tip and shank have been tested separately for disturbing the measurements when in the vicinity of the sensors. The tips of the tested instruments have a stronger influence but this decays rapidly beyond 3 cm distance from the sensor. Cutting instruments can get hot when in use. Our tests show that measurement errors are low for temperatures up to 90 degrees Celsius. Ultrasound from ultrasound probes does not seem to have any influence on measurement accuracy.