MIBG Scan

An MIBG scan is a test that helps locate and diagnose certain types of tumors. It can also show when cancer responds to therapy.

The letters MIBG stand for meta-iodobenzylguanidine. It is a protein that is absorbed by some tumors, particularly neuroblastoma. The scan can show neuroblastoma inside the body and when it has spread to the bone and other organs.

How is a MIBG scan performed?

The test has 2 parts conducted over a 2-day period, but patients do not have to be admitted into the hospital for the test.

The first day of the test, patients receive an injection of a tracer, which is the MIBG compound combined with a very small amount of a radioactive substance (radioactive iodine). Neuroblastoma cells should absorb the tracer and show up when scanned. The second day of the procedure, patients have the scan, which uses a gamma camera that takes pictures of areas where the tracer has been absorbed. Doctors look for bright spots, which may indicate cancer. 

What happens during the MIBG scan?

• On the first day, the patient receives an injection of the tracer through a vein. The patient can return to patient housing (or home) after the injection.
• The patient returns to the center the next day for the scan. There is a 24-hour waiting period to allow time for the tracer to spread throughout the body.
• The patient lies on a table and must stay still during the test, which can last 1-2 hours depending on the height of the patient. The technologist or nurse will secure the patient with soft, safety belts. The table will slowly move through a device called a scanner.
• An MIBG scan does not hurt. But the patient may find it difficult to stay still. For this reason, young children may have sedation. If patients move, the images will blur, and the test will have to be repeated.
• After the test, patients may leave and resume normal activities, unless they were sedated. Patients who had sedation must recover from anesthesia.

How should patients and families prepare for a MIBG scan?

• Medications, allergies and medical conditions: Families should inform the treatment team about the patient’s drug allergies or other medical conditions, including the possibility the patient could be pregnant. They should also tell the doctor about any medicines the patient is taking, including over-the-counter ones.
  

• Check insurance: Parents should check with their insurance provider in advance to find out how much of the test’s cost will be covered and how much parents will need to pay.
• Ask questions: Parents and patients should talk with the medical team about any concerns or questions.
• Explain procedure to patient: By the day of the scan, parents should make sure the patient knows the reason for the MIBG scan. Parents may want to consult a child life specialist to help.
• Take prescribed medicine to protect thyroid: The doctor may prescribe potassium iodide drops to start taking a few days before the injection until the day after the scan.  The drops protect thyroid from absorbing any of the radioactive iodine that is part of the MIBG.

Day of the injection

• The patient and parent should arrive a few minutes early to allow time for check-in.
• Parents may be asked to sign a consent form, which states that parents understand the benefits and risks of the scan and agree to have the test.
• The patient and parent will wait in the waiting area until they are called. A nurse or nuclear medicine technologist will greet them and explain what will happen. A child life specialist may be there as well.
• First, a nurse or technologist will inject the tracer through an IV.
• After the injection, the IV will be removed. The parent and patient may leave the area and resume normal activities.
• Pregnant women should not have direct contact with the patient from the time of the MIBG injection until instructed by the nuclear medicine staff. Most often, this is about 12 hours.

Day of the scan

• The patient should wear loose, comfortable clothing and leave jewelry and metal objects at home. Before the test, patients will remove jewelry and any other metal objects. Sometimes patients will wear a hospital gown.
• The patient and parent should arrive a few minutes early to allow time for check-in.
• Parents may be asked to sign a consent form, which states that parents understand the benefits and risks of the MIBG scan and agree to have the test.
• The patient and parent will wait in the waiting area until they are called. A nurse or nuclear medicine technologist will greet them and explain what will happen. A child life specialist may be there as well.
• The patient will lie on a table of the scanner. A gamma camera will take pictures that will help the doctors tell if there is cancer is and if it has spread to bones or other parts of the body.

After the scan

The results of the scan will be interpreted by a nuclear medicine physician. The doctor will prepare a report and share it with the physician who ordered the test. The patient’s oncologist will share the results with the family.