Selective internal radiation therapy (SIRT)

Selective internal radiation therapy (SIRT) is a way of giving radiotherapy treatment for cancer in the liver. This can be cancer that started in the liver or cancer that has spread to the liver from somewhere else. 

What is selective internal radiation therapy (SIRT)?

SIRT uses radiotherapy to control cancer in the liver that can’t be removed with surgery. It is a type of internal radiotherapy. It is sometimes called radioembolisation or trans arterial radioembolisation (TARE).

Your doctor puts tiny radioactive beads called microspheres into a blood vessel Open a glossary item. This takes blood into your liver. The beads get stuck in the small blood vessels in and around the cancer. Then the radiation destroys the cancer cells.

The radiation only travels a few millimetres from where the beads are trapped. This means it should cause little damage to the surrounding healthy tissue.

Who can have SIRT?

SIRT is available on the NHS in England for bowel cancer that has spread to the liver (liver metastases). It is for people whose bowel cancer has only spread to the liver, which can’t be removed with surgery, and chemotherapy is no longer working.

SIRT is also a treatment option in England and Wales for cancer that started in the liver. It is for a type of primary liver cancer called hepatocellular carcinoma (HCC). You might have this treatment if you have advanced HCC and:

  • your liver is working normally
  • you can’t have surgery to remove your cancer
  • you are unable to have other treatments such as trans arterial chemoembolization (TACE)

If you live in other countries of the UK, your doctor might be able to submit a funding request to see if you can have SIRT on the NHS. You might be able to have it as part of a trial, if there is one available. Or you might be able to pay for it privately.

Doctors continue to research SIRT. They are collecting information on how well it works for different types of cancers in the liver.

Tests before SIRT

Before you have SIRT, you have tests to check your liver and plan your treatment.

CT scan

A CT scan shows where the tumours are in your liver and their size. So your doctor can check that SIRT is a suitable treatment. You might not need another CT scan if you have recently had one for something else. 

Blood Tests

You have blood tests to check:

  • the number of different blood cells (a full blood count)
  • how well your kidneys and liver are working
  • there are no problems with your blood clotting

A planning angiogram

An angiogram Open a glossary item looks at the blood supply to the liver, which varies from person to person. The doctor is an interventional radiologist, who blocks off tiny blood vessels that lead to other areas of the body like the stomach or lungs. This stops the SIRT beads from travelling to other areas of the body and damaging healthy tissue. The procedure usually takes 60 to 90 minutes but may take longer.

First you might have some sedation to help you relax. Then you have an injection of local anaesthetic to numb the area at the top of your leg or your wrist. Your doctor makes a small cut and puts a catheter Open a glossary item into a blood vessel called an artery.

Your doctor guides the catheter into your liver using x-rays Open a glossary item. They then inject a contrast dye Open a glossary item to show up all the blood vessels. They can see the images on a screen. The dye might make you feel warm for a few seconds and you might feel as though you need to pass urine.

Your doctor can see if there are blood vessels that lead to other areas of the body and can block them with tiny coils. This doesn’t harm the areas that these small blood vessels go to.

Lung shunting scan

After the angiogram, your doctor injects a radioactive tracer into the catheter. The tracer is similar in size to the SIRT beads.

You then have a scan that picks up the radioactive tracer. This is called a lung shunting scan or SPECT CT. This takes about an hour. It shows where the beads will go when you have the treatment. This helps your doctor to work out if it is safe to go ahead with the treatment.

You need to lie flat for several hours after these tests if your doctor put the catheter into an artery in your groin. This helps the wound to heal. You can usually sit up straight away if they used an artery in your wrist.

You usually go home the following morning.

How you have SIRT

You have SIRT about 1 or 2 weeks after the planning angiogram.

First you have another angiogram as above. You have a sedative  Open a glossary itemto help you relax and painkillers Open a glossary item to keep you comfortable.

When the catheter is in the right place, your doctor slowly injects the radioactive beads into your liver. The whole process takes about an hour.

When your doctor removes the catheter they put a dressing over the small wound. You need to lie flat for around 6 hours if the catheter went into an artery in your groin. Most people need to stay in hospital overnight. Your nurse will give you painkillers and anti sickness medicines Open a glossary item if you need them.

You have a scan the day after treatment to check the position of the radioactive beads.

Side effects of SIRT

For most people the side effects of SIRT are mild. They include:

  • a raised temperature
  • chills
  • feeling sick
  • diarrhoea
  • stomach ache
  • a feeling of pressure in your tummy (abdomen)

These side effects usually only last a few days. Your nurse will give you medicines to help. Contact your doctor or the hospital if you develop a high temperature (above 38C) as you might have an infection.


Tiredness is a common side effect and can last up to 6 weeks. This is normally mild, so you can still do normal everyday activities. Severe tiredness is quite rare. Talk to your specialist nurse if you are worried.

Irritation to the gut

Rarely, a small number of the microspheres can travel to the digestive system (gut). This can cause:

  • pain in your abdomen
  • feeling or being sick
  • bleeding
  • a stomach ulcer
  • inflammation of the pancreas (pancreatitis)

Your doctor will give you anti ulcer medicines for around 4 to 8 weeks after treatment. This prevents irritation to the stomach.

Inflammation of the gallbladder

This is called cholecystitis. Symptoms include:

  • pain
  • fever
  • feeling or being sick

It may get better without treatment, but in rare cases you may need surgery to remove the gallbladder.

Lung damage

If the radioactive beads go to the lungs they can cause inflammation. This is very rare. It may cause a cough and shortness of breath. Your doctor might give you steroids Open a glossary item to help.

Inflammation of the liver

This can affect how well your liver works, and may happen weeks after the treatment. You will have regular blood tests Open a glossary item and liver function tests Open a glossary item to check this.

Your liver function might get better by itself after a few weeks. Or you may need steroids or other medicines. Damage to the liver can be life threatening, but this is extremely rare.

Radiation safety after SIRT treatment

For the first 24 hours after treatment you should make sure you thoroughly wash your hands after going to the toilet.

The range of radiation from the beads is very small. But as a precaution, you might be told to avoid close contact with young children and pregnant women for the first week after treatment. Your doctor might also advise you not to share a bed with your partner for the first night or two.

The advice about this can vary slightly between hospitals. Be sure to follow the instructions from your own doctor or specialist nurse.

Most of the radiation from the beads has gone within 2 weeks. The beads stay in the liver permanently but they are harmless.

Ask your doctor or nurse if you have any questions about radiation safety.

Follow up

Your specialist will follow you up closely after treatment. How they do this varies slightly between hospitals.

You will have regular blood tests to check how well your liver is working. You might have a CT scan around 2 or 3 months after treatment.

Your doctor and specialist nurse will talk to you about how often you will have check ups and scans.  

  • Analysis of a national programme for selective internal radiation therapy for colorectal cancer liver metastases
    J White and others
    Clinical Oncology, 2019. Volume 31, Pages 58-66

  • Selective internal radiation therapy for chemotherapy refractory or intolerant metastatic colorectal cancer
    NHS England, Dec 2018

  • Prevention and treatment of complications of selective internal radiation therapy: Expert guidance and systematic review
    B Sangro and others
    Hepatology, 2017. Volume 66, Issue 3. Pages 969-982

  • Localized hepatocellular carcinoma: Liver-directed therapies for nonsurgical candidates not eligible for local thermal ablation
    UpToDate, 2022
    Accessed January 2024

Last reviewed: 
11 Jan 2024
Next review due: 
11 Jan 2027

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