New form factors for sensors and field generators of a magnetic tracking system

Magnetic tracking systems can be considered an enabling technology for many image guided medical interventions, since they are not limited by line-of-sight requirements. This can allow a much deeper immersion of the technology into a particular medical navigation application. We demonstrate in this paper new prototype sensor and field generator form factors. Miniaturized sensors as small as 0.5 x 5 mm can allow integration of magnetic tracking systems into such instruments as biopsy needles, endoscopes, catheters, and guide wires. Sensors with hollow cores can surround instruments without taking up the space needed for other functions of the instrument. Such an approach shows that sensor miniaturization is not the only way to overcome space limitations in medical instruments. Flat field generators can simplify the setup of the tracking system and better optimize the location of the working volume relative to the field generator. For example, flat field generators could be built into surgical beds or into head rests. For the prototype systems considered in this paper, we discuss performance attributes such as their trueness, repeatability, and confidence limits in comparison to the standard field generator and sensors of the Aurora system of Northern Digital.