Patent ID: 8818486

Claim:
A method for locating an intra-body probe during a procedure within an organ of a living body, the method comprising: generating a magnetic field in a predefined volume; providing an intra-body probe configured to be inserted within an organ of a living body within the predefined volume, the intra-body probe comprising a field detector near a distal tip of the intra-body probe; defining an initial position vector of the distal tip of the intra-body probe within the organ of the living body; defining a reference model, which models the magnetic field at multiple points in the volume using spherical harmonics; measuring the magnetic field with the field detector of the intra-body probe within the organ of the living body located in the volume; defining a cost function by comparing the measured magnetic field with the reference magnetic field model within the volume; minimizing the cost function by a computation over dipole terms in a derivative over the cost function so as to find a position and orientation that matches the measured magnetic field; determining whether differential changes of components of a position vector of the measured magnetic field and differential changes of components of an orientation vector of the measured magnetic field are below predefined thresholds; outputting the found position and orientation as the position and orientation of the probe in the organ; and terminating tracking of the intra-body probe within the organ of the living body at termination of the procedure.