Catheter tracking system

A device for determining the position of a catheter head 16 within a body 1. The device consists of a catheter 10 having a head 16 for use in a cavity of body 1. An one or more ultrasonic transducers 18 are arranged upon the head 16 of the catheter 10 and two or more reference ultrasonic transducers 19 are arranged in/on the body in a spaced apart relation. All transducers are connected, via multichannel transceiver (24, Fig. 3), to signal processing means (22) and to computer and display means (26). In operation, ultrasonic waves are emitted from transducers 18 on the catheter, the reference transducers 19 in/on the body subsequently detect these waves (or vice versa as determined by the signal processor (22)). The time of flight of the waves propagating between the catheter transducers 18 and the reference transducers 19 is evaluated via cross-correlating the signals emitted and received by the transducers. The relative distance of the catheter transducers 18 from the reference transducers 19 is so determined. The emitted ultrasonic waves possess unique predetermined waveforms such that the signal processor (22) is able to identify the transducer from which a detected wave emanated. Contemporaneous signal detection is thus facilitated. The position of the catheter head 16 in the body 1 may be displayed on the display means (26).