MIBG scans and treatment

MIBG imaging: diagnosis and planning

An MIBG scan usually uses iodine-123 MIBG with a gamma camera, which detects radiation from the tracer. Sometimes it includes single-photon emission computed tomography (SPECT) to build three-dimensional pictures, combined with computed tomography (CT) to show body structures. This is called SPECT-CT. Pictures may be taken on more than one day. This is a different technique from a positron emission tomography (PET) scan.

The scan helps identify tissue that takes up MIBG. It can also help assess whether MIBG treatment might be useful. Imaging and treatment are separate appointments with different medicines, doses and precautions.

MIBG therapy: treating the tumour

Treatment uses iodine-131 MIBG, carrying treatment radiation into cells that take up the medicine.

The team considers whether the tumour takes up enough MIBG, alongside symptoms, disease extent, previous treatment and blood, kidney and liver tests. In some circumstances, measurements help estimate radiation delivered to the tumour and normal organs. This is called dosimetry.

The aim may be to control disease or symptoms. Ask how this option compares with other treatments available for your type of tumour. Children with neuroblastoma need a specialist plan tailored to their age, treatment and caregiving needs.

Preparing for your appointment

Ask the service to review all medicines, including cold remedies, medicines for a blocked nose, antidepressants and blood-pressure treatment. Some can interfere with MIBG uptake or affect safety. Do not stop them yourself: the team needs to decide whether a change is needed and how to make it safely.

Tell the team about hormone-related symptoms, episodes of very high blood pressure, a pounding or racing heartbeat (palpitations), headaches, urinary problems, pregnancy or breastfeeding. People with hormone-producing phaeochromocytoma or paraganglioma may need a particularly careful blood-pressure and monitoring plan.

Before admission, ask about food instructions, what belongings to bring, the likely stay, communication with family and support for children or dependent adults at home. Arrange the thyroid-blocking medicine and follow-up blood tests in advance.

Protecting your thyroid

Some radioactive iodine can become separated from MIBG and be taken up by the thyroid, a gland at the front of the neck. Non-radioactive iodine or another prescribed blocking medicine helps protect it. The team usually prescribes this protection before an MIBG scan as well as around treatment.

Take the prescribed medicine exactly as directed and ask what to do if you miss a dose or vomit. Do not substitute an iodine supplement or seaweed product. This is a different preparation from the low-iodine diet used for thyroid-cancer radioiodine treatment.

During and after treatment

The medicine is given through a drip into a vein, with monitoring. The drip and observation take time, and treatment may require several days in a room designed for radiation safety. The actual stay depends on the amount of radioactivity given and remaining in your body, your health and discharge arrangements.

Staff will explain personal care, meals, toilet use and contact with visitors. If you need physical help or feel anxious about separation, tell them before admission. Temporary radiation precautions should be planned around your care needs, not left for you to solve alone.

Side effects and when to call

Tiredness and nausea can occur. Blood counts may fall weeks later, so you still need scheduled blood tests after leaving hospital. Contact the treatment team immediately for fever, shivering or suddenly feeling very unwell. Also report unusual bruising or bleeding, marked breathlessness or severe weakness without waiting for a planned appointment. Severe headache, chest pain, a racing heartbeat or faintness needs urgent assessment, especially if your tumour produces hormones. If you cannot reach the team and need urgent help, seek urgent medical care.

Continue thyroid protection for the full prescribed period. The team may arrange later thyroid-function monitoring because thyroid problems can occur despite protection. Fertility (the ability to have children) and longer-term risks should be discussed before treatment.

After MIBG treatment

After MIBG treatment, your team will give you written advice on temporary precautions at home, including close contact, sleeping and toilet hygiene. Ask for clear dates, including any separate advice about sex, contraception (preventing pregnancy), work and travel. Tell the team if childcare or help with personal care makes these instructions difficult to follow.

Confirm your next blood-test and review dates. If you need urgent care, seek it immediately and tell staff that you have had MIBG treatment and when.

Questions you may have