At a cost of $550 per sestamibi scan and with the error inherent in the scan, it is not cost effective to obtain Tc-99m-sestamibi scan before initial surgery for primary hyperparathyroidism.Click to see full answer. Also to know is, how long does a sestamibi scan take? approximately two hours Furthermore, how accurate is a sestamibi scan? Only the overactive parathyroid gland shows upa very accurate test. The Sestamibi scan will display the hyperactive gland which is causing hyperparathyroidism in about 90 percent (90% sensitivity) of all patients. If the Sestamibi does show the hyperactive gland it is almost always correct (98-100% specificity). Keeping this in view, how long does it take to do a parathyroid scan? There are two sessions, with a 2–3-hour break in between. The first session will take about 40 minutes, and the second session about 30 minutes.Is sestamibi safe?The sestamibi scan uses low levels of radiation and is usually very safe. Sometimes, the medicine given to increase your heart rate during the stress test can cause headaches, nausea, dizziness and flushing – and these symptoms can last for a few minutes.