99mTc Sestamibi SPECT/CT vs 18F Fluorocholine PET/CT

Inclusion Criteria: 1. Suspected parathyroid adenoma (elevated serum calcium and inappropriately normal or high levels of parathyroid hormone) 2. Negative or equivocal 99mTc Sestamibi SPECT/CT 3. Able to provide written consent 4. Total bilirubin ≤ 1.5 x upper limit of normal (ULN) 5. Alanine aminotransferase (ALT) or aspartate aminotransferase (AST) ≤ 5 xULN 6. Karnofsky performance status of \>50 (or ECOG/WHO equivalent) 7. Women must not be pregnant per the Department of Radiology Policy on Imaging in Potentially Pregnant and Pregnant Women. Exclusion Criteria: 1. Less than 18 years old at the time of radiotracer administration 2. Creatinine clearance (calculated using Cockcroft-Gault formula, or measured) \< 60 mL/min or serum creatinine \>1.5 x ULN 3. QTcF \>470 msec on electrocardiogram (ECG) or congenital long QT syndrome