Intraoperative, low-cost optical sensor for rapid assessment of blood perfusion in parathyroid glands

Thyroidectomy is a surgical procedure that removes the diseased part of the thyroid gland and is approximately performed over 93,000 in the US. Hypocalcemia (low calcium level in blood) is one of the most common post-operative complications, caused by accidental damage or removal of the parathyroid gland (PTGs) during thyroidectomy, which could lead to lifelong strains on patients. PTGs controls the calcium levels in our body, so any damage or removal of the PTGs can reduce calcium levels. Currently, it is challenging to predict hypocalcemia after surgery and surgeons rely on their visual inspection to determine PTG viability, which is a subjective and unreliable method. The purpose of this project is to build a portable, low-cost intraoperative device, that can accurately and rapidly provide surgeons with the information about the perfusion of the PTGs, indicative of PTGs viability. The device utilizes an optical technique called Speckle Contrast Optical Spectroscopy (SCOS). SCOS uses a laser coherent light to non-invasively measure the Blood Flow Index (BFI) by observing the speckle contrast pattern created by light scattering from the moving red blood cells. The device is constructed of four main components including a processing unit, fiber optic cable, laser diode, and compact camera. To demonstrate the basic feasibility, we have performed the computational verification on SCOS technique by simulating experimental conditions with different exposure times (0.2-2 ms) and source-detector separations (0.3 and 0.6 cm) on a wide range of tissue BFI indices. The estimation accuracy in BFI via our analytical approach is less than ~10% on the simulated noisy SCOS data. Now, the experimental verification using the optical phantoms mimicking tissue blood flow and optical properties is ongoing. We envision that this device has the potential to address the technological gap in quantitative, non-invasive, and affordable intraoperative tools for PTG variability