PTH and familial hypocalciuric hypercalcemia: The mean PTH and calcium concentrations at the time of 18F-FCH PET/CT were 118 pg/mL (range: 15–746) and 2.54 mmol/L (range: 2.22–3.05), respectively; 4/42 (10%) patients had multiple endocrine neoplasia type-1 (MEN-1), and 1/42 (2%) had familial hypocalciuric hypercalcemia (FHH).