Intraoperative Assessment of Surgical Margins in Cancer Resection Surgery Via the Sub-Diffuse Optical Tomography "S-DOT"

Abstract

In Head and Neck Squamous Cell Carcinomas (HNSCC), positive margins after surgical resection dominate the clinical outcome of patients. Between 15-30 precent of all HNSCC surgeries result in a positive margin (>5mm) that requires postoperative chemo-radiation, radiotherapy, and/or revision surgeries. To minimize local recurrence, margin assessment is typically performed through surgical pathology departments; however, this technique often takes more than 24 hours to process and only a small fraction of the total surgical margin is evaluated. A second, intraoperativeapproach used by surgeons to minimize local recurrence is frozen section analysis (FSA), which in time intensive and suffers heavily from sampling errors. To effect change, we have hypothesized a sub-diffuse optical tomography modality that can identify the differences in depth sensitivity of the fluorescence, Cetuximab-IRDye800CW conjugate (ICON), by the fluorescent photons collected from sub-diffused media as a function of the photon exit angle from the excited tissue. Based on promising preliminary simulations using Monte Carlo MATLAB, closed vs. open aperture fluorescence imaging in biological tissue demonstrated an enhanced true depth of fluorescence resolution up to 6mm, well beyond the insufficient 5mm mark. By identifying the deep margins from the fluorescent peaks within 5 minutes, we hope to improve complete oncological surgery by providing surgeons an exact region of interest on the specimen where the tumor is closest to the edge, so they may continue surgery by providing sugeons an exact region of interest on the specimen where the tumor is closest to the edge, so they may continue surgery on the spot to minimize the probability of cancer being left behind.