Types of external radiotherapy
Proton beam therapy is a type of radiotherapy treatment. It uses high energy or low energy proton beams to treat cancer. It is a treatment for some types of cancer. Most people don’t need to have proton beam therapy and have external radiotherapy using high energy x-rays (photons).
There is a low energy proton machine in Clatterbridge which treats some eye cancers.
More information about low energy proton beam therapy for eye cancer
The rest of this page is about high energy proton beam therapy which is used to treat some other types of cancer.
Up until recently everyone needing high energy proton beam therapy had to go abroad for treatment.
In 2009, the UK government made the decision to set up a National NHS Proton Beam Therapy Service. Currently there are two centres offering high energy proton beam treatment for anyone needing it in the UK. This is available at:
The Christie NHS Foundation Trust in Manchester
University College London Hospital (UCLH) in London
Proton beam therapy is also available in private treatment centres in the UK. So you would have to pay for this treatment or use private insurance if you have it.
Go to the NHS booklet about receiving proton beam therapy abroad
Proton beam therapy is only suitable for certain types of cancer. This includes some very rare types and cancers close to vital or delicate parts of the body. These are areas where it is important to do as little damage to surrounding healthy cells as possible. This helps to prevent serious complications.
For adults this includes cancers that develop at the base of the skull or near the spine.
For children, teenagers and young adults the list is longer. Your child might have proton beam radiotherapy if they have some types of:
brain cancer
spinal cord cancer
cancers that develop in the head and neck area
A part of the proton machine called a gantry directs proton beams at the area of the body that needs treating. Protons are tiny particles from the centre of atoms. They can only be seen under a special microscope.
Protons treat cancer by producing a sudden burst of energy when they stop. So by directing the proton beams at a cancer and making them stop inside the tumour, they destroy the cancer. And cause little damage to the nearby healthy cells.
A course of treatment can last between 3 to 7 weeks. It depends on your type of cancer. Your doctor will discuss this with you.
You usually have proton beam therapy every day from Monday to Friday. Each treatment usually takes between 30 to 60 minutes. Sometimes you may need to have treatment at the weekend.
If you live a long way from the treatment centre, accommodation is available for you to stay at throughout your treatment.
Before you have your treatment, you have an assessment and meet the team caring for you. The assessment can take a few days.
You have 1 or 2 CT scans and possibly an MRI scan. Your doctor uses these to plan your proton beam therapy.
Find out more about planning radiotherapy
You may need a mask made if you are having treatment to your head or neck. Or you may have a mould on a different part of your body. They are also called shells. They keep the treatment area of your body still each time you have radiotherapy. So your treatment is as accurate as possible.
Read more about radiotherapy masks and moulds
The proton beam machine is very big and may make you feel nervous when you see it for the first time. Some machines can rotate 360 degrees. This allows it to accurately aim the proton beam to the area needing treatment.
Before your first treatment your radiographers explain what you will see and hear. The treatment rooms may have docks for you to plug in music players. So you can listen to your own music or audio books while you have treatment.
Having the treatment
It is important you are in the right position for the treatment. So your radiographers may take a little while to get you ready. You can help by trying to relax as much as possible during this time.
Once you are in the right position your radiographers stand behind a screen in the room. They take some X-rays to check you are in the correct position.
They then leave you alone in the room. This is so they are not exposed to the radiation. You’ll be alone for a few minutes or up to 15 minutes, depending on the length of the treatment. Your radiographers tell you how long the treatment will take.
Your radiographers watch you carefully on a closed circuit television (CCTV) screen. They can hear you as well. You can’t feel anything while you’re having treatment, but you’ll hear the machine.
The Christie hospital have made a short video showing how you have proton beam therapy.
Watch the Christie hospital video about having proton beam therapy
The side effects depend on which part of your body is being treated.
In general, you may feel tired during treatment and for a short while afterwards. You might lose your hair in the treatment area and your skin might become sore and red.
Before the treatment, your doctor will go through the possible side effects with you. They will explain how long they might last and how they can help treat them.
As with any radiotherapy there may be some long term effects. Your doctor will go through these with you. The risk of these side effects may be less than with other external radiotherapy.
Research continues to look at how well proton beam therapy works and the possible side effects.
After proton beam therapy you may have your follow up appointments at the PBT centre or at your local hospital. You have any further treatment, such as chemotherapy or surgery, at your usual cancer treatment centre.
Your radiographers might ask you to fill out some questionnaires about your treatment and any side effects. This will help them with future research.
Last reviewed: 10 Nov 2023
Next review due: 10 Nov 2026
External radiotherapy means having radiation from a machine outside the eye. Find out when you might have it and how it works.
Your radiotherapy team carefully work out how much radiation you need. They plan the treatment using scans to see exactly where the radiotherapy beam needs to be directed.
You might have moulds or masks made for you before you start radiotherapy. Find out about the different types and how they are made.
External radiotherapy targets radiation at the cancer from a radiotherapy machine. Read about types of external radiotherapy and what happens during planning.
Radiotherapy is a common treatment for children’s brain tumours. Find out what type of radiotherapy they might have, what happens before, during and after radiotherapy.
Find out about cancer treatment with radiotherapy, including external radiotherapy, internal radiotherapy, side effects, radiotherapy for symptoms and follow up after treatment.
About Cancer generously supported by Dangoor Education since 2010. Learn more about Dangoor Education
What to ask your doctor about clinical trials.
Meet and chat to other cancer people affected by cancer.
Questions about cancer? Call freephone 0808 800 40 40 from 9 to 5 - Monday to Friday. Alternatively, you can email us.
