Medical instrument identification

A medical instrument tracking system, comprising:

• a medical instrument including a handle and different rigid interchangeable heads for individual insertion into the handle, the handle having a handle position-tracking transducer disposed thereon, different respective ones of the interchangeable heads having differently positioned respective head position-tracking transducers disposed thereon so as when proximal ends of the different respective ones of the interchangeable heads are inserted into a distal end of the handle, the different respective head position-tracking transducers define different respective distal positions relative to the handle position-tracking transducer;
• and
• processing circuitry configured to:
• receive signals generated by the handle position-tracking transducer and the respective head position-tracking transducer of a respective one of the interchangeable heads inserted into the handle;
• compute a relative position between the handle position-tracking transducer and the head position-tracking transducer of the inserted interchangeable head responsively to the received signals;
• receive a user identification of the inserted interchangeable head via a user input device;
• and
• associate the user identification of the inserted interchangeable head with the computed relative position so as to allow future identification of the inserted interchangeable head being reinserted into the handle responsively to a new computed relative position being within a given tolerance of the computed relative position.

A method for medical treatment using a medical instrument including a handle and different rigid interchangeable heads for individual insertion into the handle, the handle having a handle position-tracking transducer disposed thereon, different respective ones of the interchangeable heads having differently positioned respective head position-tracking transducers disposed thereon so as when the different respective ones of the interchangeable heads are inserted into the handle, the different respective head position-tracking transducers define different respective positions relative to the handle position-tracking transducer, wherein the medical instrument is configured for inserting into a body part of a living subject, the method comprising:

• receiving signals generated by the handle position-tracking transducer and the respective head position-tracking transducer of a respective one of the interchangeable heads inserted into the handle;
• computing a relative position between the handle position-tracking transducer and the head position-tracking transducer of the inserted interchangeable head responsively to the received signals;
• identifying which one of the interchangeable heads is inserted into the handle responsively to the computed relative position;
• transmitting alternating magnetic fields into a region where the body-part is located, the head position-tracking transducer of each of the interchangeable heads includes at least one coil;
• and
• detecting at least part of the transmitted alternating magnetic fields by the at least one coil.