Types of external beam radiotherapy

How you have radiotherapy will depend on what type of cancer you have, and where it is in the body. There are different types of external beam radiotherapy including:

  • conformal – shapes the radiotherapy beams to fit the treatment area
  • intensity modulated radiotherapy treatment (IMRT) – shapes the radiotherapy beams and gives different doses to different parts of the treatment area
  • volumetric-modulated arc therapy (ARC) – the machine moves around you during treatment
  • image-guided radiotherapy (IGRT) – uses images taken before treatment to check the position of the treatment area
  • 4D – takes images during treatment to adjust for movement such as breathing
  • stereotactic radiotherapy (SBRT or SABR) – uses lots of small beams to target the tumour
  • total body irradiation (TBI) – a single dose of radiation is given to the whole body
  • proton beam radiotherapy – uses proton radiation rather than x-rays
  • intraoperative radiotherapy – a single dose of radiation given during surgery to remove a cancer.

Some of these are newer treatment that may not be available in all hospitals. Your cancer doctor, nurse or radiographer can tell you which type of radiotherapy is suitable for you.

Types of external beam radiotherapy

There are different ways of having external radiotherapy. How you are given your treatment will depend on: 

  • the type of cancer you have
  • the part of the body that needs treating.

Your clinical oncologist or radiographer can tell you more about these treatments and whether they are suitable for you. If a type of radiotherapy is not available at your local hospital, they may arrange for you to have it at another treatment centre.

Radiotherapy explained

Consultant Clinical Oncologist Vincent Khoo describes external beam radiotherapy, how it works, and what it involves.

Information about our videos

Radiotherapy explained

Consultant Clinical Oncologist Vincent Khoo describes external beam radiotherapy, how it works, and what it involves.

Information about our videos


Conformal radiotherapy

Many types of external beam radiotherapy are conformal. This means the beams are specially shaped to fit the treatment area.

Conformal radiotherapy can be used to treat many different types of cancer.


Intensity-modulated radiotherapy (IMRT)

IMRT shapes the radiotherapy beams and allows different doses of radiotherapy to be given to different parts of the treatment area. This means lower doses of radiotherapy are given to the healthy tissue surrounding the tumour. This can help reduce the risk of side effects and late effects. It may also allow higher doses of radiotherapy to be given to the tumour.

IMRT is often used to treat tumours that are close to important organs or structures. This is because it may reduce damage to healthy tissue and side effects. For example, it may be used to treat pelvic tumours because it can reduce the risk of long-term bowel problems. IMRT may also be used for head and neck tumours. This is to reduce damage to the salivary glands and the risk of having a dry mouth permanently.

Many treatment centres in the UK provide IMRT. It is mainly used to treat breast, head and neck, anal, prostate, bladder, gynaecological and lung cancers.


Volumetric-modulated arc radiotherapy (VMAT)

VMAT is a newer way of giving IMRT. It is sometimes called RapidArc®. The radiotherapy machine moves around you and reshapes the beam during treatment. This makes it more accurate and shortens the treatment time.


Image guided radiotherapy (IGRT)

IGRT uses the pictures from scans taken before, and sometimes during, each treatment. The pictures are compared to those taken during the planning scan to check your position and the treatment area.

IGRT is helpful for treating tumours in areas of the body that change shape or position during or between treatment sessions. For example, it may be used to treat the prostate or cervix. This is because their positions can change if you have a full bladder or bowel on the day of your treatment. IGRT means the radiographers can adjust the treatment area before each treatment. This makes the radiotherapy very precise.


4D radiotherapy (four-dimensional radiotherapy)

4D radiotherapy uses a radiotherapy machine that takes pictures during your treatment. The pictures show any movement of the tumour.

4D radiotherapy is helpful for treating tumours in areas of the body that move during treatment. For example, these could be tumours in the lung that move as you breathe. The radiotherapy team use the information from the pictures to adjust the radiotherapy treatment area during your treatment.

This treatment is not yet available in all radiotherapy centres.

There are other ways to help reduce movement in the treatment area. Your radiographer may show you some breathing techniques. Or they may use gentle compression on your tummy area, depending on where you are having treatment. They will do this during planning and treatment. It helps to reduce movement in the area being treated. This allows them to treat the area more accurately.


Stereotactic radiotherapy

Stereotactic radiotherapy uses many small beams of radiation to target the tumour. This makes it very precise. It means high doses of radiotherapy can be given to very small areas of the body. This can reduce the risk of side effects.

Stereotactic radiotherapy is used to treat different types of tumours. You may be offered this treatment as part of a research trial.

This treatment may not be available in all radiotherapy centres. Your radiotherapy team will give you more information if this treatment is suitable for the type of cancer you have.

We have more information about stereotactic radiotherapy.


Total body irradiation (TBI)

TBI treatment is when a large single dose of radiation, or 6 to 8 smaller doses, is given to the whole body. This type of radiotherapy is not used very often. It is sometimes given to people who are having a stem cell transplant.

We have more information about TBI.


Proton beam therapy

Proton beam therapy uses proton radiation rather than x-rays to destroy cancer cells. Proton beams can be made to stop when they reach the area being treated. This is different to standard radiotherapy beams, which pass through the area and some healthy tissue around it. Using proton beam radiotherapy may help to reduce side effects and the risk of long-term effects.

Proton beam therapy is only suitable for a small number of people. It is available at the Clatterbridge Cancer Centre in Wirral to treat tumours of the eye.

It has been available for certain other types of cancer at the Christie Hospital in Manchester from late 2018. It will also be available at University College Hospital in London from 2020. Until these treatment centres are fully available, some people who need this type of radiation may be able to have it in America or Europe, paid for by the NHS.

Your radiotherapy team will give you more information if proton beam therapy is suitable for the type of cancer you have.


Intraoperative radiotherapy

Intraoperative radiotherapy is when a single dose of radiation is given during surgery to remove a cancer. It is given in the operating theatre.

This treatment is still being researched and may only be available as part of a research trial. It may be an option in some situations. For example, it may be used for women with early breast cancer who would normally have radiotherapy after surgery.

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