Fused EIT handheld probe localizes oral cancer margins to within 0.5 mm

A new study from Dartmouth researchers introduces a fused electrical impedance tomography (EIT) approach for intraoperative oral cancer margin assessment. Oral squamous cell carcinoma (OSCC) often results in positive surgical margins, which significantly worsen patient outcomes. The team, led by Sophie A. Lloyd, combined EIT measurements from an electromagnetically tracked handheld probe to reconstruct tumor boundaries more accurately than single-site imaging. EIT distinguishes cancerous tissue from healthy tissue based on electrical conductivity differences, offering a real-time, radiation-free alternative to preoperative imaging.

Through simulations, noise analysis, and physical phantom experiments, the researchers compared several reconstruction methods for fusing multi-site probe data. Fused approaches recovered the conductivity boundary location to within 0.5 mm of the true boundary, a dramatic improvement in localization accuracy. Notably, fused difference EIT proved most robust to all added noise types, thanks to the high data redundancy inherent in its reconstruction formulation. This suggests that a handheld probe combining electromagnetic tracking with EIT could reliably map the entire tumor boundary during surgery. The results, published on arXiv and submitted to Physiological Measurement, are a meaningful step toward a clinically deployable impedance imaging system—one that could help surgeons achieve complete resection and reduce recurrence risk for OSCC patients.