A wireless and handheld optical palpation imaging probe for use in breast-conserving surgery

We present a wireless and handheld optical elastography probe aimed toward improving intraoperative discrimination between malignant and benign tissue in breast-conserving surgery. If successful, this probe can contribute to reducing close or positive margins and, therefore, subsequent re-excisions. The probe visualizes mechanical contrast between tumor and surrounding benign tissue in excised human breast specimens using stereoscopic optical palpation, in which the deformation of a compliant silicone layer is measured by two parallel cameras to infer surface stress, where variations in stress correspond to differences in the mechanical properties of the underlying tissue. Wireless operation is achieved using a Wi-Fi transceiver to transmit images at 15 fps to a laptop for processing. To enhance image quality, we incorporate computational optical palpation, which utilizes finite element analysis to provide a more accurate mechanical model of the deformation of the compliant layer. This approach yields a twofold improvement in spatial resolution, from 1034 to 512 μm, and a 55% increase in stress contrast in a structured silicone phantom. In a preliminary study on four excised human breast tissue samples, we demonstrate that the probe can identify tumor and distinguish between benign tissue types, including adipose tissue, stroma, and potentially ducts.