A wide range of medical procedures involve placing objects, such as sensors, tubes, catheters, dispensing devices and implants, within the body. Position sensing systems have been developed for tracking such objects. Magnetic position sensing is one of the methods known in the art. In magnetic position sensing, magnetic field generators are typically placed at known positions external to the patient. One or more magnetic field sensors within the distal end of a probe generate electrical signals in response to these magnetic fields, which are processed in order to determine the position coordinates of the distal end of the probe. These methods and systems are described in U.S. Pat. Nos. 5,391,199, 6,690,963, 6,484,118, 6,239,724, 6,618,612 and 6,332,089, in PCT International Publication WO 1996/005768, and in U.S. Patent Application Publications 2002/0065455 A1, 2003/0120150 A1 and 2004/0068178 A1, whose disclosures are all incorporated herein by reference.
U.S. Pat. No. 6,370,411, whose disclosure is incorporated herein by reference, describes a probe having two parts: a catheter of minimal complexity which is inserted into a patient's body, and a connection cable that connects between the proximal end of the catheter and the console. The catheter comprises a microcircuit that carries substantially only information specific to the catheter, which is not in common with other catheters of the same model. The cable comprises an access circuit which receives the information from the catheter and passes it in a suitable form to the console. In some embodiments, the cable operates with all catheters of a specific model or type, and therefore when a catheter is replaced, there is no need to replace the cable. Catheters that are planned for one-time use do not require replacement of the cable, which does not come in contact with patients.
U.S. Patent Application Publication 2006/0074289 A1, whose disclosure is incorporated herein by reference, discusses an endoscopic probe, whose handle has an orientation sensor that generates signals indicative of the orientation of the handle in an external frame of reference. The output of the orientation sensor may be used to sense movement of the handle relative to its initial position and orientation at the beginning of the endoscopic procedure.