99mTc-Sestamibi (MIBI) parathyroid imaging is currently the most widely used preoperative nuclear imaging procedure to localize hyperfunctioning parathyroid glands in patients with hyperthyroidism. Since MIBI tracer accumulates within the mitochondrial cells, the higher abundance of mitochondrial cells within the oxyphil cells of the parathyroid glands enables increased MIBI accumulation in the hyperfunctioning glands. The sensitivity of the MIBI scan is enhanced by using single photon emission computed tomography/computed tomography (SPECT/CT), pinpointing the hyperfunctioning glands at typical or ectopic sites, especially useful in multiglandular disease. In patients with recurrent disease, second operation is often more technically challenging than the first one, thus precise preoperative localization is important. Still, the sensitivity of the MIBI SPECT/CT is greater for adenomas than hyperplasia or multiglandular disease, which could be due to smaller size of the hyperplastic glands and rapid parathyroid wash-out of radiotracer in some lesions. Combining cervical ultrasound and MIBI SPECT/CT, a sensitivity of 81-95% can be reached. A meta-analysis showed pooled detection rate of 88% using MIBI SPECT/CT, especially in patients with primary hyperparathyroidism. In cases of negative or equivocal findings in parathyroid MIBI SPECT/CT, an alternative method using 18F-fluorocholine (FCH) PET may be used. The higher resolution of PET/CT imaging compared to SPECT/CT improves lesion detection. Choline is a precursor of phosphatidylcholine, which is involved in the biosynthesis of phospholipids, essential components of cell membrane. Tumor or adenomas show increased cell membrane turnover, which increase FCH uptake. A meta-analysis involving 517 patients (12 studies) showed pooled sensitivity, PPV, and detection rate of 95%, 97%, and 91%, respectively on a per-patient analysis. Per-lesion analysis showed pooled sensitivity of 92% and PPV of 92%. Head to head comparison demonstrated superior sensitivity of FCH PET/CT compared to MIBI SPECT/CT in primary hyperparathyroidism. Further studies shown good efficacy of FCH PET/CT in patients with inconclusive MIBI SPECT/CT findings, identifying lesions <10mm in diameter. In addition to better spatial resolution, FCH PET/CT show lower radiation exposure and shorter acquisition time than MIBI SPECT/CT.