Depth sensing capabilities of an interoperative impedance sensing probe

Providing information on the depth of positive surgical margins and important underlying anatomic features would help guide surgeons to resect tissue to negative margins, while sparing healthy tissue needed to preserve function. In transoral robotic surgery, surgeons lack haptic feedback which would be used to locate tumor boundaries and underlying critical structures. An interoperative electrical impedance sensing probe has the potential to provide highly specific tissue classification and 3D imagery. This would enable surgeons to visualize tumor boundaries in reference to critical anatomy (e.g., neurovasculature features) during oral cancer resection and help optimize oncological outcomes without sacrificing functional outcomes for patients. This paper focuses on characterizing the depth sensing capabilities of an impedance sensing probe designed for intraoperative deployment. Electrical impedance tomography (EIT) images were reconstructed from simulation and experimental data of a half-plane inclusion moving away from the probe surface. The developed probe successfully sensed changes in conductivity up to 6 mm away from the probe face. Future work includes increasing reconstruction resolution and validating performance with phantoms simulating hidden vasculature in tissue.