MIBG Scan

What is an MIBG scan?

An MIBG scan is a test that uses a radioactive substance to make images of neuroendocrine tumors. These tumors include:

• Neuroblastoma
• Pheochromocytoma
• Paraganglioma

An MIBG scan is also called adrenal medullary imaging, I-123 MIBG scan, or I-131 MIBG scan.

An MIBG scan is different than MIBG therapy. MIBG therapy uses a higher dose of a radioactive substance to treat neuroblastoma and other neuroendocrine tumors.

Learn more about MIBG therapy.

How a MIBG scan works

MIBG stands for metaiodobenzylguanidine. It is a liquid taken up by neuroendocrine tumor cells. MIBG is combined with radioactive iodine (I-123 or I-131) to make a radioactive substance called a tracer. The tracer is given as an injection through an IV. A special camera takes pictures to show where the tracer was absorbed by tumor cells.  

These images show where the tumor cells are in the body. This scan can show if cancer has spread to the bone or other organs. It can also show if tumors respond to therapy.

Before the MIBG scan

• Talk to your care team: Be sure to ask questions and talk to your care team about any concerns. Let your care team know if your child has any allergies, other medical conditions, is sexually active, or could be pregnant.
• Check insurance: If you have private health insurance, contact them to find out how much insurance will cover and how much you will need to pay.
• Explain the test to your child: Make sure your child knows the reason for the MIBG scan and what to expect. You may want to ask a child life specialist to help.
• Take prescribed medicine to protect the thyroid: Your health care provider will prescribe potassium iodide drops (SSKI solution). The drops protect your child's thyroid gland from absorbing any radioactive iodine. Your child will take the medicine before they get radioactive tracer injection through the day after the scan.

Medicines and MIBG scans

Let your care team know about all medicines (even over-the-counter ones), vitamins, and supplements your child takes. 

A pharmacy team member will contact you to review your child’s medicines. They will tell you if your child needs to stop taking any medicines.

Some medicines can interfere with an MIBG scan. These include some types of:

• Antidepressants
  • Amitriptyline (Elavil^®)
    
  • Imipramine (Tofranil^®)
  • Desipramine (Norpramin^®)
  • Nortriptyline (Aventyl® or Pamelor^®)
• Anti-nausea medicines
  • Promethazine (Phenergan^®)
  • Prochlorperazine (Compazine^® or Compro^®)
• Blood pressure medicines
  • Labetalol (Trandate^®) – Should be avoided for at least 6 weeks before an MIBG injection. Tell the care team right away if your child takes this medicine.
• Other medicines:
  • Chlorpromazine (Thorazine^® or Largactil^®)
    
  • Thioridazine (Mellaril^®)
  • Haloperidol (Haldol^®)

Your child should not take medicine with pseudoephedrine or phenylephrine. These are found in many over-the-counter cold medicines. These substances can interfere with the scan.

Do not stop giving your child any medicines before you talk to the care team. Talk with your child’s doctor, nurse, or a member of the pharmacy team if you have questions.

How to prepare for an MIBG scan

Each care center has its own procedures. Talk to your care team about what to expect and how to get ready for your appointment.

• Talk to your child about staying still: It is important that your child knows what to expect. They will need to lie still during the test. A child life specialist or other care team member might help your child with relaxation techniques.
• Comfort items: Most centers will let you bring a comfort item like a stuffed animal or a blanket. Ask your care team if that is OK.
• Eating and drinking before the scan: Follow your care team’s instructions for what your child can eat or drink before the scan. If your child is going to have general anesthesia, they must not eat or drink (NPO) for several hours before the test. Your child’s care team will give you more specific instructions.
• Check in for the appointment: Be sure to arrive a few minutes early. Check in at the registration desk with your child. You may be asked to sign a consent form. Then you will wait until your child’s name is called.
• Be sure to let the care team know if your child:
  • Is uncomfortable in small spaces
  • Has trouble staying still or has specific behavior needs 
  • Might be pregnant
  • Is allergic to contrast agents or iodine
  • Has diabetes or kidney problems
• What to wear: Be sure your child dresses in loose, comfortable clothing. Avoid clothing and accessories that contain metal. Do not wear:
  • Belts
  • Zippers
  • Snaps
  • Buttons
  • Hair accessories
  • Watch
  • Jewelry
  • A non-permanent retainer 
  • Glasses

In some cases, your child may need to change into a hospital gown.

What to expect during an MIBG scan

The test takes place over 2 days. Your child does not have to be admitted into the hospital for the test.

Day 1: Injection of the radioactive tracer

Your child will get a tracer injection through a vein by IV. The injection includes MIBG combined with a small amount of radioactive iodine. Tumor cells should absorb the tracer and show up when scanned the next day.

You and your child can return home (or to patient housing) and resume normal activities. 

You will wait 24 hours to allow time for the tracer to move through the body.

Day 2: Imaging scan

You and your child will return to the care center for the scan. The care center may have movies that your child can watch during the test. You may want to bring books, devices, toys, or comfort items that your child likes. If the care team says it is OK, you may also want to bring a snack or a drink for after the test.

Your child will lie very still on a table during the test. The care team may secure your child with soft safety belts. A child who finds it hard to stay still might need sedation or general anesthesia. If your child moves during the test, the scan will blur and must be repeated. 

A special camera will take pictures of the inside of the body. The camera will move around close to your child’s body. It will not touch your child. The scan takes pictures of areas that absorbed the tracer.  

When the scan is done, a care provider will unfasten safety belts and disconnect the IV, if one was used.

An MIBG scan does not hurt. The test can last 1–2 hours, depending on your child’s size.

After the test, your child can go home. If your child had medicines for sedation or general anesthesia, they will need to recover first. 

After the MIBG scan

After the scan, your child can go back to normal activities. The test uses a small dose of radiation, so it is important to follow your care team’s instructions before, during, and after the MIBG scan. This will include your child drinking lots of water to clear out the radioactive tracer from the body.

A doctor called a nuclear medicine physician or radiologist will study the images and prepare a report of the results. The report may take a few days. Your health care provider will talk with you about the MIBG scan. 

Possible risks of MIBG scans

The MIBG scan is a nuclear medicine test. It uses a small amount of radioactive iodine. Nuclear medicine specialists carefully select the amount of tracer used. They want to have an accurate test with the least possible radiation exposure.

The amount of tracer depends on:

• Your child’s body weight
• Reason for the scan
• Body part being imaged

Questions to ask your care team

• Is an MIBG scan safe for my child?
• How long does the MIBG scan take?
• What are the instructions before, during, and after the scan?
• Will my child need anesthesia for an MIBG scan?
• Does an MIBG scan hurt?
• Can my child watch a movie or listen to music during the scan?
• Is it safe to be around my child after they get the tracer?
• How long will it take to get MIBG test results?

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