Catheter tracking in an interventional photoacoustic surgical system

In laparoscopic medical procedures, accurate tracking of interventional tools such as catheters are necessary. Current practice for tracking catheters often involve using fluoroscopy, which is best avoided to minimize radiation dose to the patient and the surgical team. Photoacoustic imaging is an emerging imaging modality that can be used for this purpose and does not currently have a general tool tracking solution. Photoacoustic-based catheter tracking would increase its attractiveness, by providing both an imaging and tracking solution. We present a catheter tracking method based on the photoacoustic effect. Photoacoustic markers are simultaneously observed by a stereo camera as well as a piezoelectric element attached to the tip of a catheter. The signals received by the piezoelectric element can be used to compute its position relative to the photoacoustic markers using multilateration. This combined information can be processed to localize the position of the piezoelectric element with respect to the stereo camera system. We presented the methods to enable this work and demonstrated precisions of 1-3mm and a relative accuracy of less than 4% in four independent locations, which are comparable to conventional systems. In addition, we also showed in another experiment a reconstruction precision up to 0.4mm and an estimated accuracy up to 0.5mm. Future work will include simulations to better evaluate this method and its challenges and the development of concurrent photoacoustic marker projection and its associated methods.