Evaluation and analysis of thyroid uptake as detected by Ga-68 DOTATATE PET/CT

The Ga-68 DOTATATE scans were performed as previously described (9,10). Five mCi of Ga-68 DOTATATE was administered through a peripheral vein. After approximately 60 minutes, the patient was placed in a supine position in a PET/CT scanner (Siemens Medical Solutions USA, Inc., Malvern, PA), and images from the upper thighs to mid-skull (including pituitary gland) were obtained. A low-dose, non-contrast CT was used for attenuation correction and anatomic localization. Maximum standardized uptake value (SUV_max) levels were measured based on patient total body weight.

Two providers independently reviewed all of the Ga-68 DOTATATE PET/CT scans and classified the thyroid uptake status. The blinded reads were compared, and a board-certified nuclear medicine physician (C.M.) provided validation of all imaging assessments. Thyroid uptake was classified as diffuse or focal. Normal thyroid uptake was defined as having a SUV_max that was below that of the liver and salivary glands. Abnormally increased uptake was defined as focal and diffuse uptake, with SUV_max levels greater than those of the liver or salivary glands.