There are 4 parathyroid glands in the neck and they are responsible for the production of parathyroid hormone which maintains calcium homeostasis throughout the body. They are difficult to identify relative to the other tissues in the neck such as lymph nodes, fat, thyroid etc. This has resulted in the incidence of accidental parathyroid removal ranging from 8% to 19% of patients undergoing total thyroidectomy . Damage to the parathyroid gland(s) can cause hypoparathyroidism and hypocalcemia resulting in serious and deleterious side effects. There are 3 different surgery procedures in the neck region where a key part of surgery protocol is for the surgeon to visually identify the parathyroid clearly to avoid accidental injury and removal. These are Thyroidectomy (involving partial or complete removal of thyroid), Parathyroidectomy (involving removal of one or more parathyroid glands) and modified Neck Dissection (involving removal of lymph nodes in neck into which cancer has spread). In a recent discovery, the PI Prof. Mahadevan-Jansen's group at Vanderbilt University reported for the first time the breakthrough finding that the Parathyroid Gland has a unique autofluorescence signature in the NIR under illumination at 785nm. The Phase 1 research demonstrated a prototype platform based on this technology that could do point detection and imaging.
The specific aims of this proposal is to build upon that work and it seeks to a) Develop a product that can function in two modes: ? A point detection mode that can be used to confirm if a candidate tissue is parathyroid or not ? An imaging mode that can be used to look at a region to guide the surgeon to then using the point detection mode to confirm b) To investigate the use of the auto-fluorescence technology to assess lymph nodes intra-operatively for cancer metastases. c) To detect parathyroid vascularization via diffuse reflectance spectroscopy
The goals of this project is to build an intra-operative imager and detector that can uniquely detect the parathyroid glands and thus prevent their accidental removal since they are difficult to distinguish relative to other neck tissues such as lymph nodes, fat, thyroid etc. There are around 100,000 thyroid surgeries each year in the US to remove part or all of the thyroid. Up to 20% of these surgeries lead to accidental removal of the parathyroid glands. This costs the US healthcare system about $200Mill/yr. annually that this project can help address. The specific aims of the proposed STTR P2 project, when achieved, will yield a intra-operative detector capable of imaging and identifying the parathyroid glands. This will reduce injury due to accidental or incomplete removal of parathyroid tissue and an additional aim will help in assessing lymph nodes for cancer metastasis so as to prevent unnecessary lymph node removal: Specific Aim (1a): To design and build the point detection product that can be used to identity parathyroid intra-operatively to prevent accidental injury and removal. Our objective here is to build a real-time point detection product that can work at illumination laser powers below 5mW so that we can obtain the eye-safe Class 3R rating enabling the product to be used without laser safety goggles. We have shown proof of concept of this in Phase 1 and our goal is to engineer the product from that prototype. If successful, this product has the potential to save the US health care system at least $200 Mill/yr. via reduced hospital stays post-surgery. Specific Aim (1b): To design and build a product that can be used for imaging of tissue to identify the parathyroid within a field of view which can then be touched with a probe to confirm that it is the parathyroid. Our objective here is to build a combined point detection and imaging product so as to enable the surgeon to scan a larger region to identify possible parathyroid candidates from the image and use the point probe to confirm. We will explore two paths here. One is more risky but much more simple and inexpensive. The other is less risky but will lead to a slightly more expensive product. If successful, this product has the potential t save the US health care system at least $200 Mill/yr. via reduced hospital stays post-surgery. Specific Aim (2): To use the autofluorescence technology for lymph node cancer assessment during thyroid cancer surgery our preliminary data showed that patients with metastatic disease showed an increased fluorescence in the lymph node spectra, potentially due to the presence of infiltrating cancer cells that originate from the thyroid or parathyroid. Our objective here is to verify in a systematic study of 15 patients that the autofluorescence technology can be used to detect Lymph node metastases. Currently available techniques simply lack the sensitivity to detect all lymph metastases pre-operatively, correctly identifying lymph node involvement in only 15-30% of patients. This leads many endocrine surgeons to advocate prophylactic lymph node dissection leading to increased morbidity