A Novel Approach to Ultrafast Parathyroid SPECT Imaging Using a Solid State CZT SPECT Camera

Single-tracer, dual-phase Tc-MIBI parathyroid scintigraphy is based on the differential washout rate of the tracer (MIBI) from the thyroid and the parathyroid tissue. A distinct focus of increased MIBI uptake relative to the thyroid gland, either on the early or late image or on both, or a focal uptake in the mediastinum, is considered positive for abnormal parathyroid tissue. Tc99m-MIBI planar scintigraphy was found to play a major role in the preoperative localization of a parathyroid adenoma (PTA), with a sensitivity ranging from 85% to 95% and specificity of up to 99%. Subsequently, the use of MIBI- Single photon emission computed tomography (SPECT) significantly improved the sensitivity of the test and improved the accuracy of lesion localization.

A limitation of adding the SPECT component is related to its relatively long duration. The duration of a MIBI-SPECT acquisition of neck and the mediastinal area may take up to 15-20 minutes using a standard nuclear medicine camera. Long acquisition time may lead to patient discomfort and movement resulting in image degradation, artifacts and may lead to overall decreased diagnostic accuracy.

A reduced SPECT acquisition time without image quality degradation may decrease patient discomfort and increase clinical throughput. An ultrafast solid state CZT camera (GE Healthcare Discovery 570C) is currently used for routine cardiac SPECT imaging achieving high quality cardiac studies for a significantly shorter acquisition time. Present study evaluates the potential use of the ultrafast camera in patients with a clinically suspected PTA who perform Tc-MIBI imaging.