What is selective internal radiation therapy (SIRT)?

SIRT is a type of internal radiotherapy. It may be used to treat the following:

  • Cancer that has spread to the liver from the large bowel. It may sometimes also be used to treat cancer that has spread to the liver from other places in the body.
  • Some cancers that started in the liver (primary liver cancer).

SIRT uses radioactive beads. It is also called radioembolisation. It is not the same as chemoembolisation, which is also called TACE or CT-ACE. This uses chemotherapy and sometimes plastic beads.

SIRT is not always available on the NHS. Your cancer team will tell you if it is available for you. You may have to travel to a specialist hospital to have it. You may have it as part of a clinical trial

We have more information about how cancer treatments are made available and what you can do if a treatment is not available.

How does SIRT work?

Tiny radioactive beads are injected into the bloodstream. They stick permanently in the small blood vessels in and around the liver tumour. The beads give off radiation, which damages the cancer cells.

The radioactivity of each bead only affects tissue that is very nearby. This means cancer cells near the beads will be most affected. Some healthy cells may also be affected. Your team will decide how many radioactive beads to inject to try to reduce the risk of damage to healthy cells.

The beads lose their radioactivity quickly and are most effective in the first few days. They stay in the body permanently, but this does not cause any problems.

SIRT with chemotherapy

SIRT may be given at the same time as chemotherapy. Having these treatments together may work better. This is because they work in different ways. But it may also increase some of the side effects.

Your doctor will explain if SIRT with chemotherapy is suitable for you. They can tell you how any side effects will be managed.

We have more information about chemotherapy side effects.

Tests before SIRT treatment

Your doctor will arrange tests before you have treatment. These help your team to decide whether you will benefit from SIRT. The tests also help plan your treatment.

Blood tests

A sample of your blood is taken to check:

  • the levels of different types of cells in your blood – this is called a full blood count
  • how well your kidneys and liver are working
  • how quickly your blood clots.

If you have bowel cancer, your blood may also be tested for a protein, or tumour marker called carcinoembryonic antigen (CEA). Some people with bowel cancer have higher levels of this protein. So, doctors may check this regularly to see how well a treatment for bowel cancer is working.

If you are having SIRT for hepatocellular carcinoma, your blood may be tested for a tumour marker called alpha fetoprotein (AFP).

We have more information about blood tests.


You will usually have CTMRI or PET scans. These check how much of the liver is affected by the tumour. They also check whether there is cancer in other areas of the body. This information helps your team plan the treatment.

Planning angiogram

An angiogram is a test that uses x-rays to look at blood vessels. A planning angiogram shows the blood supply to your liver. This may also be called a pre-SIRT angiogram. It helps your doctor see where the SIRT beads would go when they are injected.

You have this test in the x-ray (radiology) department of the hospital. You may be asked not to eat or drink anything for several hours before. Your team will also give you instructions about any medication you usually take. This includes drugs that thin your blood, such as aspirin or warfarin.

You will have a local anaesthetic injection to numb the skin on one side of the groin or wrist. The doctor then makes a small cut in the skin. They gently put a thin, flexible tube called a catheter into a blood vessel in the groin or wrist. The catheter is guided up the blood vessel to the liver.

The doctor injects dye into the catheter and takes x-rays to see where the dye goes. This shows where the SIRT beads would travel in the bloodstream. The doctor uses tools through the catheter. Sometimes they may close off any small blood vessels that would take the beads away from the tumour to other parts of the body. This does not harm the areas that are closed off.

The doctor then injects a liquid called a radioactive tracer. After the angiogram, you have a scan that finds this liquid. It shows where the SIRT beads will go to in the liver. It also checks that none would escape from the liver to other parts of the body, such as the bowel or lungs. This helps your doctor know if it is safe for you to have the treatment. If the scan finds tracer outside the liver, you may need another planning angiogram before you have SIRT. You pass the radioactive tracer in your urine (pee). It does not cause damage to you or anyone that you come into contact with.

If the cut was made in the groin, you have to lie flat for a few hours after the angiogram. If the cut was made on the wrist, you can sit up straight away. Try to drink at least 1½ litres (3 pints) of water in the 24 hours after your test. This helps clear the dye from your body.

Your team will tell you what you can and cannot do after the test. Usually, you should:

  • not drive for 24 hours after the test
  • avoid heavy lifting and vigorous exercise for 3 days.

Having SIRT

You usually have the treatment 1 to 2 weeks after the planning angiogram.

You are awake for the treatment. Some people have medication to help them relax. This may make you feel sleepy. You may also have an anti-sickness medicine. You have another angiogram, and SIRT beads are injected into the catheter. This usually takes less than an hour. If you have any pain during the treatment, let your doctor or nurse know. They can give you painkillers.

You may need to stay in hospital overnight, or for a few days. Before you go home, your doctor or nurse will explain any medication you need to take. Some medications are to reduce the chance of serious side effects. It is important to let your team know if you cannot take them. They will also explain any possible side effects and who to contact if you need advice.

SIRT beads
Image: SIRT beads

Radiation safety after SIRT

Your healthcare team will plan your treatment to give you the amount of radiation needed to treat the cancer safely and effectively. But your team are also careful to protect other people around you from radiation. Safety measures may be slightly different in different hospitals. Your team will tell you what to expect.

Almost all the radiation from each SIRT bead is absorbed by the area of the body closest to it. But your body fluids will be slightly radioactive for a time. It is safe for you to be around most other people. But you may have to avoid close contact with children or anyone that is pregnant for a while.

Your team will explain this and any other safety measures you need to know about or follow at home. This may include instructions about:

  • using the toilet and cleaning up any spilled body fluids safely
  • not sharing a bed or having sex for a few days
  • not breastfeeding or using expressed breast milk (milk you have stored to feed your baby later) for a few weeks.

Your team will also give you information to carry with details of your treatment.

Contraception and SIRT

Your doctor will advise you not to get pregnant or make someone pregnant while having this treatment. This is because radiation may harm a developing baby. It is important to use contraception to prevent pregnancy for at least 2 months after you have SIRT.

Your team will give you more information about this.

Possible side effects of SIRT

We explain the most common side effects of this treatment here. You may get some of the side effects we mention, but you are unlikely to get all of them. These side effects are usually short-term and get better with time.

You may also have some side effects that we have not listed here. Always tell your doctor, nurse or pharmacist about any side effects you have.

Rarely, SIRT can cause side effects that start weeks after treatment. Sometimes these may be serious or need treatment straight away. Your team will explain these to you.

Problems at the injection site

There may be bruising or a small lump where the angiogram catheter went into the groin or wrist. You should let your nurse or doctor know straight away if you notice any:

  • bleeding
  • redness
  • swelling
  • discharge
  • pain.

Feeling sick (nausea)

You may be given an anti-sickness drug to prevent nausea before you have SIRT. Tell your doctor or nurse if you feel sick after treatment. They can give you tablets to help. Nausea usually only lasts for a few days.

Tummy (abdominal) pain

Some people have tummy pain during SIRT. Tell your doctor or nurse about any pain you have during or after treatment. They can give you painkillers to help.

Rarely, some beads may escape from the liver to the stomach or bowel. This can irritate the lining of the stomach or bowel and cause tummy pain or indigestion. You may be given medicine to take regularly. This will help. Tell your doctor or nurse straight away about any pain.

High temperature or infection

This treatment can cause a high temperature for a few days. Fever is a common side effect of SIRT, but it can also be a sign of infection.

When you are home, contact the hospital straight away on the contact number you have been given if:

  • your temperature goes over 37.5°C (99.5°F)
  • your temperature goes below 36°C (96.8°F)
  • you suddenly feel unwell, even with a normal temperature
  • you have symptoms of an infection – this can include feeling shaky, a sore throat, a cough, diarrhoea or needing to pass urine (pee) a lot.

Tiredness (fatigue)

Tiredness can last from a few days up to several weeks after treatment. It is important to get enough rest and eat a balanced diet to help your body recover. Keeping a fatigue diary can help you record your energy levels and plan activities for when you are feeling stronger. We have more information about coping with tiredness.

Changes to the liver

SIRT can affect normal liver cells. This may cause changes to how the liver works. You will have regular blood tests to check this. Changes usually get better after a few weeks. Rarely, they can get worse after about 4 to 6 weeks.

Follow-up care after SIRT

You will have further tests after SIRT to see how well your treatment has worked. This may include more blood tests and scans. Some people have a second treatment of SIRT. Your doctor will explain if this is needed. We have more information about lifestyle and well-being after cancer treatment.

Getting support

Macmillan is here to support you. If you would like to talk, you can do the following:

About our information

  • References

    Below is a sample of the sources used in our radiotherapy and selective internal radiation therapy (SIRT) information. If you would like more information about the sources we use, please contact us at cancerinformationteam@macmillan.org.uk

    National Institute for Health and Excellence (NICE). Selective internal radiation therapies for treating hepatocellular carcinoma. Published 31 March 2021. Available from www.nice.org.uk/guidance/ta688 (accessed October 2021).

    National Institute for Health and Excellence (NICE). Selective internal radiation therapy for unresectable colorectal metastases in the liver. Published 04 March 2020. Available from www.nice.org.uk/guidance/ipg672 (accessed October 2021).

  • Reviewers

    This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been reviewed by expert medical and health professionals and people living with cancer. It has been approved by Senior Medical Editor, Dr David Gilligan, Consultant Clinical Oncologist.

    Our cancer information has been awarded the PIF TICK. Created by the Patient Information Forum, this quality mark shows we meet PIF’s 10 criteria for trustworthy health information.

Date reviewed

Reviewed: 01 August 2022
Next review: 01 August 2025
Trusted Information Creator - Patient Information Forum
Trusted Information Creator - Patient Information Forum

Our cancer information meets the PIF TICK quality mark.

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