ADAPTIVE FLUOROSCOPE LOCATION FOR THE APPLICATION OF FIELD COMPENSATION

摘要

Compensation for a field-perturbing element in a magnetic tracking system for locating a probe is achieved by creating a reaction field model while the field-perturbing element is in known positions. A magnetic field location sensor is disposed between the field-perturbing element and magnetic field generators of the tracking system. Magnetic field readings from the location sensor and from a magnetic field sensor on the probe are taken while the field-perturbing element is present. The position of the field-perturbing element is estimated from the location sensor readings, and a predicted reaction field calculated from the reaction field model. A compensated measurement is obtained by subtracting the predicted reaction field from the field detected by the location sensor. The readings from the probe sensor are adjusted using the compensated measurement in order to calculate the true position of the probe.

主权项

1. A method, comprising the steps of:
in a calibration phase performing the steps of: generating a magnetic field in a region using a plurality of magnetic field generators; placing a field-perturbing element in known positions within the region; and creating a reaction field model by calculating respective reaction magnetic fields while the field-perturbing element is in the known positions; and in an operational phase performing the steps of: placing the field-perturbing element in a new position within the region; disposing a magnetic field location sensor between the field-perturbing element and the magnetic field generators; introducing a distal segment of a probe into the region, a probe magnetic field sensor being disposed on the distal segment; regenerating a perturbed magnetic field with the magnetic field generators; obtaining first measurements of the perturbed magnetic field from the probe magnetic field sensor; obtaining second measurements of the perturbed magnetic field from the location sensor; reconstructing the new position of the field-perturbing element from the second measurements; obtaining a predicted reaction magnetic field for the reconstructed new position from the reaction field model; obtaining a compensated measurement by subtracting the predicted reaction magnetic field from the second measurements; adjusting the first measurements according to the compensated measurement; and calculating a position of the probe magnetic field sensor using the adjusted first measurements.