Dual-phase parathyroid scintigraphy using [99mTc]Tc-MIBI represents a widely established functional imaging technique for localizing hyperfunctioning parathyroid glands in patients with hyperparathyroidism. This approach employs the differential washout of the radiopharmaceutical between thyroid and parathyroid tissues. While single-tracer dual-phase protocols offer worldwide availability and straightforward implementation, dual-tracer [99mTc]Tc-MIBI techniques demonstrate superior diagnostic performance, particularly in challenging cases and in the presence of thyroid abnormalities. The integration of single-photon emission computed tomography (computed tomography (SPECT/CT) significantly enhances anatomical localization and reduces false-positive and false-negative results. However, both approaches show limitations in detecting multiglandular disease and hyperplasia, commonly encountered in secondary hyperparathyroidism. Notably, PET imaging with [18F]fluorocholine ([18F]FCH) has emerged as a superior one-stop-shop imaging method with excellent sensitivity, even in cases where conventional scintigraphy fails. Despite its initial higher costs, 18F-fluorocholine positron emission tomography/computed tomography (PET/CT) offers significant advantages in challenging patients, including those with multiglandular disease, a history of neck surgery, or thyroid abnormalities. This chapter reviews the radiopharmaceutical characteristics, methodological procedures, image analysis techniques, and comparative advantages of these complementary approaches, emphasizing the ongoing trend toward more sensitive and accurate preoperative parathyroid localization methods that significantly impact surgical planning and patient outcomes.