What is a SPECT scan?

SPECT stands for single-photon emission computerized tomography. This radiographic scan is a type of nuclear imaging test, meaning that a radioactive drug is injected into the blood stream and a special camera is used to take images of the organs. This test is better than a conventional X-ray because it produces a 3-D image of an organ and shows function for the organ. This test may occasionally be recommended in the evaluation of parathyroid disease when other diagnostic imaging has been inconclusive.

How does it work? The radiotracer (radioactive drug) is absorbed by active tissues in the body. The more active a tissue, the more radiotracer absorbed. Therefore an overactive parathyroid gland is going to absorb more radiotracer than normal parathyroid glands and other, less active tissues in the neck. Tissues that take up more radiotracer will appear a darker color on the image, allowing the physician to pinpoint the abnormal glands, organs, or tissues. This radiotracer is very similar to the one used in a sestamibi scan.

The risks of this type of scan are very low. Because there is an injection, there may be pain or swelling at the injection site. Rarely, an allergic reaction to the radioactive drug may occur. There is a low amount or radiation exposure associated with this test.