Training of impedance based location system using registered catheter images

A method, comprising:

• inserting a first catheter having at least one electrode and at least one coil into a chamber of a body organ of a patient;
• recording at a sequence of times respective sets of currents between the at least one electrode and a plurality of patches positioned on skin of the patient;
• while recording the sets of currents, acquiring x-ray images of the at least one electrode and the plurality of patches, and determining locations of the catheter from the images;
• while recording the sets of currents, recording signals generated in the at least one coil in response to magnetic fields irradiating the catheter, and determining measures of the locations in response to the signals;
• deriving a relation between the locations and the sets of currents based on the sets of currents, the signals, and the images;
• removing the first catheter and inserting a second catheter having a second-catheter-at-least-one-electrode and no coil into the body organ;
• recording subsequent sets of currents between the second-catheter-at-least-one-electrode and the patches;
• and
• determining, based on the relation, subsequent locations of the second catheter in response to the subsequent set of currents.

Apparatus, comprising:

• a catheter having at least one electrode which is configured to be inserted into a chamber of a body organ of a patient;
• and
• a processor, which is configured to:
• record at a sequence of times respective sets of currents between the at least one electrode and a plurality of patches positioned on skin of the patient,
• while recording the sets of currents, acquire x-ray images of the at least one electrode and the plurality of patches, and determine locations of the catheter from the images,
• derive a relation between the locations and the respective sets of currents based on the sets of currents and the images,
• record subsequent sets of currents between the at least one electrode and the patches, and
• determine, based on the relation, subsequent locations of the catheter in response to the subsequent set of currents.