Parathyroid Scan

Parathyroid Sestamibi Scan

Parathyroid sestamibi scanning is always performed before minimally invasive parathyroid surgery. Sestamibi is a small protein which is labeled with the radio-pharmaceutical technetium-99m. This very safe and mild radioactive agent is then preferably absorbed by the abnormal parathyroid gland i.e. parathyroid adenoma. Using a technically advanced gamma nuclear camera, the abnormal gland can then be visualized and localized in the neck. Normal parathyroid glands typically will not take up the radioactive particles because they are suppressed by an elevated calcium level caused by the abnormal gland . Therefore, a sestamibi scan will show the one bad parathyroid tumor and it will NOT show your normal parathyroid glands. The other 3 parathyroids are essentially sleeping and not functioning at a normal state. The normal parathyroids produce relatively minimal parathyroid hormone.

This can be an extremely accurate and sensitive test; when performed correctly with the latest equipment it localizes approximately 70% of parathyroid adenomas. If this test is done at a hospital with less experience, the percent of positive scans decreases. If this nuclear scan is positive, there is a greater than 95% specificity i.e. it is very likely that the active area of the scan represents the parathyroid adenoma.