An MIBG scintiscan is a type of imaging test. It uses a radioactive substance (called a tracer) and a scanner to find or confirm the presence of pheochromocytoma and neuroblastoma. These are types of tumors that affect nerve tissue.
How the Test is Performed
A radioisotope (MIBG, iodine-131-meta-iodobenzylguanidine, or iodine-123-meta-iodobenzylguanidine) is injected into a vein. This compound attaches to specific tumor cells.
You will have the scan later that day or the next day. For this part of the test, you lie on a table under the arm of the scanner. Your abdomen is scanned. You may need to return for repeated scans for 1 to 3 days. Each scan takes 1 to 2 hours.
Before or during the test, you may be given an iodine mixture. This prevents your thyroid gland from absorbing too much of the radioisotope.
How to Prepare for the Test
You will need to sign an informed consent form. You will be asked to wear a hospital gown or loose-fitting clothes. You will need to remove jewelry or metal objects before each scan. Many drugs interfere with the test. Ask your health care provider which of your regular medicines you may need to stop taking before the test.
How the Test will Feel
You will feel a sharp needle prick when the material is injected. The table may be cold or hard. You must lie still during the scan.
Why the Test is Performed
This test is done to help diagnose pheochromocytoma when an abdominal CT scan does not give a definite answer. It is also used to help diagnose neuroblastoma.
There are no signs of a tumor.
What Abnormal Results Mean
Most often, this test is used to locate pheochromocytoma.
It may also be used to detect multiple tumors or tumors that are located outside the adrenal tissues.
The test may also be done for other conditions, such as multiple endocrine neoplasia (MEN) II.
There is some exposure to radiation from the radioisotope. The radiation from this radioisotope is higher than from many others. You may need to take extra precautions for a few days after the test. Your provider will tell you what actions to take.
Before or during the test, you may be given an iodine solution to help keep your thyroid gland from absorbing too much iodine.
This test should NOT be done on pregnant women because of the danger from radiation to the unborn baby.
Adrenal medullary imaging; Meta-iodobenzylguanidine scintiscan
Hutton BF, Segerman D, Miles KA. Radionuclide imaging. In: Adam A, Dixon AK, Gillard JH, et al, eds.Grainger & Allison's Diagnostic Radiology: A Textbook of Medical Imaging
Young WF Jr. Adrenal medulla, catecholamines, and pheochromocytoma. In: Goldman L, Ausiello D, eds.Goldman's Cecil Medicine
Update Date 10/22/2014
Updated by: Jason Levy, MD, Northside Radiology Associates, Atlanta, GA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.