The NIH-funded project period has come to an end.

It is often challenging to tell apart the parathyroid glands from the surrounding area such as lymph nodes, fat and thyroid tissue. If the surgeons are not able to tell where the parathyroid glands are, they might accidentally be removed or damaged. This can lead to complications such as hypocalcemia (low calcium level) requiring treatment and sometimes lead to longer hospital stay. This study is designed to test a new method (a non-invasive hand-held imaging device) to assist surgeons in identifying the parathyroid glands, in order to decrease the rate of post-operative complication.

In thyroid surgeries, it is often difficult to visually distinguish parathyroid glands (PTGs) from the surrounding anatomical structures in surgeries because of their small size and appearance that is similar to lymph nodes, fat, and thyroid tissue. Unfortunately, even with surgeons' abundant experience in thyroidectomies, unintentional injury or removal of PTGs is frequently identified due to the subjective and inconclusive localization of PTGs. Such accidental removal or injury of PTGs may lead to serious complications such as postoperative hypocalcemia or hypoparathyroidism. Therefore, there is a clear need to provide surgeons with intraoperative surgical guidance to safely identify PTGs in order to prevent the risk of surgical complications.

To meet this need, we aim to assess the ability of a new non-invasive, probe-based Hand-Held Imager (HHI) [hANDY-i, Optosurgical, LLC] to identify PTGs intraoperatively in order to help surgeons safely preserve PTGs in surgeries. Using Near-Infrared Autofluorescence Imaging (NIRAF), HHI's camera system will detect spontaneous autofluorescence signals without injection of any contrast. The probe component of the HHI will allow surgeons to conveniently and noninvasively navigate deeper areas where PTGs are difficult to reach. Should the HHI be able to discriminate PTGs from surrounding anatomical structures in the neck, the investigators hypothesize that surgeons will be better equipped to distinguish surgical margins of pathological tissue for safe resection in challenging thyroid surgeries.

Furthermore, in order to confirm the perfusion status of the PTGs indocyanine green (ICG) angiography imaging will be utilized in select cases where the blood supply deemed to be compromised, this will enable the surgeon to decide if the gland is still viable.

Inclusion Criteria:

• Diagnosis of thyroid tumors, or other conditions requiring thyroid surgery where frozen section biopsy of PTGs is deemed necessary under the surgeon's estimation.
• Plan for surgical resection of pathological PTGs.
• Subject age 18 - 70 yo.
• Subject agreement to participate

Exclusion Criteria:

• Not eligible for endocrine surgeries
• Plan for biopsy only of thyroid tumor (likely difficult to obtain sufficient tissue for both pathology analysis and study assessment)
• Subject age younger than 18 yo or older than 70 yo
• Subject refusal to participate
• Subject cognitively impaired and/or unable to provide assent.
• Allergy to indocyanine green and iodine.

Data review for each subject will be completed shortly after enrollment. The research data will not include the participant's contact or identifying information. Rather, individual participants and their research data will be identified by a unique study identification number. The study data entry and study management systems used by research staff will be secured and password protected. At the end of the study, all study databases will be archived at Johns Hopkins Hospital.