Different types of radiotherapy

Several different types of radiotherapy machines are used to give radiotherapy. Radiotherapy beams can be shaped to fit the area being treated. This allows doctors to deliver the correct dose of radiotherapy to the area affected by cancer, while damaging as little of the surrounding healthy tissue as possible. This helps reduce side effects.

There are a number of different types of external radiotherapy:

  • Conformal radiotherapy uses a device inside the radiotherapy machine to shape the radiotherapy beams to fit the treatment area.
  • Intensity modulated radiation therapy (IMRT) shapes the radiotherapy beams and allows different doses of radiotherapy to be given to different parts of the treatment area. This makes it very useful for treating cancers that are close to important organs or structures.
  • Image guided radiotherapy (IGRT) uses images, taken using an x-ray or CT scan machine, to show the size, shape and location of the tumour just before treatment.

Your medical team will decide which type of radiotherapy is most suitable for you.

Different types of external radiotherapy

The type of radiotherapy you have will depend on the type of cancer you have, and which part of the body needs treating.


Conformal radiotherapy

This uses a device inside the radiotherapy machine to shape the radiotherapy beams to fit the treatment area. Conformal radiotherapy is used to treat a number of different cancers, including cancers of the head and neck, prostate, gullet (oesophagus), some types of lung cancer, breast cancer and brain tumours.


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 can be given to healthy tissue, particularly healthy tissue that’s more easily damaged by radiotherapy. As a result, immediate and long-term side effects are reduced. Because IMRT can reduce damage to healthy tissue and side effects, it’s often used to treat tumours that are close to important organs or structures. For example, when IMRT is used to treat pelvic tumours, it can reduce the risk of long-term bowel problems. When it’s used for head and neck tumours, it can reduce damage to the salivary glands and the risk of permanent mouth dryness. It may also allow higher doses of radiotherapy to be given to the tumour.

Many, but not all, treatment centres in the UK provide IMRT for people that need it. It’s generally accepted that IMRT should be used for 3 in every 10 (30%) people who are having curative treatment. It’s mainly used to treat breast, head and neck, prostate, bladder and lung cancers. You can find out more about IMRT and whether it’s a suitable treatment for you from your clinical oncologist. They can arrange for you to have IMRT at another treatment centre if it’s not possible for you to have it at your local centre.


Image guided radiotherapy (IGRT)

Before, and sometimes during, a course of radiotherapy, images are taken to make sure the treatment accurately targets the treatment area. With IGRT, images are taken just before each treatment. This may involve taking x-ray images or moving the machine around you to get an image similar to a CT scan. The images can be compared to those taken during the planning scan. They are used to make adjustments to the treatment area, making it very precise.

IGRT is helpful because some tumours can shrink in size and change shape during the treatment. Others can change position between treatment sessions. For example, the position of a tumour in the prostate gland or cervix can be altered by a full bladder or bowel on the day of your treatment. With IGRT, adjustments can be made before each treatment to allow for these changes to the tumour shape or position. Every person should have IGRT as part of their treatment. How it’s carried out varies in different radiotherapy centres. You may want to ask your team for more information about how IGRT is being used to check your treatment is accurate.


Back to External beam radiotherapy explained

What is external beam radiotherapy?

External beam radiotherapy is the most common type of radiotherapy. A big machine directs external radiotherapy beams at the affected area.

Making a radiotherapy mask

During radiotherapy to the head and neck a mask is used to help you keep still so that exactly the right area is treated.

Stereotactic ablative radiotherapy (SABR)

Stereotactic ablative radiotherapy (SABR) is a treatment that uses scans and specialist equipment to precisely target certain cancers. It is usually only suitable for smaller cancers.