Wireless, hand-held diffuse reflectance spectroscopy for intraoperative assessment of the parathyroid glands viability

27% of thyroid surgeries in the United States result in temporary or permanent hypocalcemia (a lack of calcium in the blood) due to complications during surgery which damage the parathyroid glands (PTG). There’s an unmet clinical need for technology that can rapidly and quantitatively assess the viability of the PTG during surgery. We propose a hand-held wireless diffuse reflectance spectroscopy (DRS) device as a solution to address this need. DRS is a noninvasive optical technique to quantify tissue optical properties. In DRS, broad-band white light is delivered to biological tissues. The reflected light spectrum is recorded using a spectrometer. This gives insight into the physiological state of the interrogated tissues. Traditionally, DRS is performed using fiber optic probes. However, fiber optic probes are expensive and fragile. Alternatively, we have tested a non-contact handheld wireless spectrometer system (LinkSquare®, Stratio Inc) To analyze the measured tissue reflectance spectra using LinkSquare®, we have employed a Monte Carlo-based Lookup Tables (MCLUT) approach. ZEMAX is an optical software that simulates single photon raytracing in three-dimensional space. We constructed an MCLUT for both the fiber optic probe based and LinkSquare® geometries using simulated reflectance data from 441 combinations of reduced scattering and absorption coefficients (0-50/cm). We have verified both geometries on a liquid blood phantom which mimics the optical properties of the PTG (comprised of hemoglobin, intralipid, and water). We have controlled the oxygen saturation (SO2) using a yeast and a glucose and measured the diffuse reflectance at different values. We observed the distinctive spectral differences in the measured reflectance during deoxygenation. Our next step is to apply our MCLUT-based inverse model to estimate the absolute SO2 values after calibrating the experimental data. We envision that this novel hand-held tool will assist surgeons to rapidly and objectively evaluate the PTG health resulting in improved surgical outcomes