Catheter position tracking system using planar magnetics and closed loop current control

Abstract

This paper presents an electromagnetic system for five degrees of freedom position and orientation sensing with application in a virtual bronchoscopy system. Planar magnetic source coils were manufactured on printed circuit boards for reproducibility and low-cost manufacturing. The exact magnetic field of each coil is calculated using a filament-based approach. A constant ac current amplifier is used to drive each coil at an independent frequency and a synchronous demodulator calculates each associated magnetic field component using the current waveform as a reference signal. Commercially available search coil sensors are used and a comparison between shielded and unshielded probes is presented. Extensive testing with two separate methods has shown the accuracy of the system to be between 1 and 2 mm. The use of a novel closed loop coil driver has been found to offer excellent magnetic field stability and significant reduction in crosstalk interference. © 2014 IEEE.