Tc-99m-sestamibi/Tc-99mpertechnetate dual-tracer scintigraphy of parathyroid glands with double image subtraction: A dedicated short execution time protocol

Author(s): Feras Chehade*,Ali Kanj, Elias Ghafari, Nasser Hammoud, Najla Fakhereddine, Ahmad Ghazzawi, Hilal Abou Zeinab, Khalil Jaber, Hassan Kazma7 & Hamza Chehade

Objective: Parathyroid scintigraphy is one of the most common imaging techniques utilized for preoperative detection of hyperfunctioning parathyroid glands. Since 1980, numerous scintigraphic protocols have been used with no established uniform technique. Majority of these techniques expressed by the gamma camera occupation time and the patient presence time in the nuclear medicine facilities last at least 3 to 4 hours. We describe an in-house short execution time scintigraphic protocol, lasting 1 hour and using dualtracer with double image subtraction.

Methods: Our in-house protocol is based on the acquisition of multiple images view of the cervical and mediastinal regions, after successive intravenous injections of Tc-99m-sestamibi and Tc-99m-pertechnetate to detect and localize either orthotopic or ectopic hyper functioning parathyroid glands. Double subtraction of thyroid region images allows visualization of parathyroid lesions. Six representative positive cases of our protocol were selected among 286 cases enrolled between January 2017 and December 2019 with clinically and biologically documented hyperparathyroidism and being candidates for surgery.

Results: In 5 cases of primary and 1 case of secondary hyperparathyroidism, there was a tendency of linear correlation between the activity level of the true positive foci, the size of gland documented by histology, and the serum levels of parathyroid hormone and calcium. The false-positive foci of activity revealed by our protocol are related to motion artifact or concomitance of a multi-nodular thyroid goiter.

Conclusion: According to an extensive comparative review of the literature data, the main technical particularities of our challenging protocol lie in its promising performance, short execution time, and low cost.