Nuclear medicine sestamibi parathyroid imaging is now a standard preoperative assessment for patients with hyperparathyroidism. Since the introduction of Technetium-99m (99mTc) sestamibi for parathyroid imaging in 1989 there has been a steady refinement in the imaging technique. The accuracy is determined by the scan technique employed, with the dual-isotope (123Iodine/99mTc sestamibi)scan providing better accuracy than the simpler sestamibi washout method. Now the pathologic parathyroid process can be localized preoperatively with great confidence, limiting the time and extent of the neck dissection and allowing a significant number of parathyroid surgeries to be performed as outpatient procedures.