Catheters are commonly used in many procedures and tracking and localizing them is critical to patient safety and surgical success. The standard of care for catheter tracking is with the use of fluoroscopy. Alternatives using conventional tracking technologies such as electromagnetic trackers have been previously explored. This work explores the use of an emerging imaging modality, photoacoustics, as a means for tracking. A piezoelectric (PZT) sensor is placed at the tip of the catheter, allowing it to receive the acoustic signals generated from photoacoustic markers due to the photoacoustic effect. The locations of these photoacoustic markers are determined by a stereo-camera and the received acoustic signals are converted into distances between the PZT element and the photoacoustic markers. The location of the PZT sensor can be uniquely determined following a multilateration process. This work validates this photoacoustic tracking method in phantom, simulation, and in vivo scenarios using metrics including reconstruction precision, relative accuracy, estimated accuracy, and leave-out accuracy. Submillimeter tracking results were achieved in phantom experiments. Simulation studies evaluated various physical parameters relating to the photoacoustic source and the PZT sensor. In vivo results showed feasibility for the eventual deployment of this technology.
Keywords: catheter tracking; image-guided procedures; interventional tool guidance; photoacoustics.