A method and apparatus for electromagnetic navigation of a surgical probe near a metal object. The electromagnetic navigation system includes a transmitter coil array and a shield. The transmitter coil array has a plurality of transmitter coils and is operable to generate the electromagnetic field to...http://www.google.com/patents/US20040116803?utm_source=gb-gplus-sharePatent US20040116803 - Method and apparatus for electromagnetic navigation of a surgical probe near a metal object
