Tracking performance and surgeon assessment of photoacoustic-based surgical guidance methods

Photoacoustic imaging has the potential to provide real-time surgical guidance to avoid ureteral injury during hysterectomies, including photoacoustic-based distance measurements and auditory alerts to warn surgeons of unsafe proximity. Validation of tool tip tracking performance and assessments of surgeon interaction with multiple feedback options derived from photoacoustic-based tool tip tracking are essential to assess the expected impact.

Tracked tool tip positions were compared with ground-truth data acquired to validate our recently proposed velocity-based tracking approach. A user study with gynecological surgeons, OB/GYN residents, and a control group of non-medical professionals was then performed to determine the extent of improvements that can be achieved with multiple photoacoustic-based feedback techniques derived from the proposed velocity-based tracking approach.

The average mean tracking errors across various programmed tool motions were 0.24 mm and 0.56 mm in the lateral and axial dimensions, respectively. Combinations of photoacoustic-based distance measurements, auditory feedback, and photoacoustic video display improved correct classifications of tool-to-ureter distances by 11.1% to 48.1% and reduced the aggregated response times among users by 1.72-2.15 s (i.e., 37-47% improvement) relative to camera videos.

Results are promising for the continued development of a photoacoustic surgical guidance system that successfully mitigates ureteral injuries during hysterectomies, simultaneously enabling reduced reliance on subjective camera-based visualization and addressing limitations of depth perception in conventional surgical imaging. This integration of photoacoustic image guidance into intraoperative workflows has the potential to enhance surgical safety.