Radiotherapy for adults

If you have been diagnosed with a brain tumour, there are a variety of possible treatment options. One of these is radiotherapy. It may be used on its own, or in conjunction with other treatment options, such as neurosurgery or chemotherapy.

For information about radiotherapy for children, visit our radiotherapy for children page.

What is Radiotherapy?

Radiotherapy uses controlled doses of invisible, high energy beams of charged particles to destroy tumour cells whilst causing as little damage as possible to surrounding cells.

It may be used:

  • where surgery isn't possible
  • after surgery to kill any remaining tumour cells
  • to prevent a tumour from returning
  • to slow down the growth of the tumour.

Stereotactic radiotherapy

Read more about stereotactic radiotherapy, which uses computers and scanners to produce 3D images that very accurately locate a tumour within the brain and direct radiotherapy treatment towards it.

Before radiotherapy treatment

Planning your radiotherapy

Your radiotherapy is very carefully planned by a team of medical specialists to ensure that it reaches and destroys as many of the tumour cells as possible, whilst damaging as little of the healthy tissue as possible.

As part of the planning, you may have several scans. The image and measurements from the scan help the team create a 3D image showing the precise location and shape of the tumour. This allows the tumour to be targeted more precisely.

The scans also help your health team plan how your treatment should be staged. This means how many sessions of radiotherapy you'll need and how much radiation to give at each session. This is important as it makes sure the normal cells have time to recover before the next dose of radiation.

Treatment mask

To make sure the radiotherapy is directed to the correct part of your brain, it's important that you stay very still during the treatment. To help you do this, a tailor-made treatment mask holds your head in position each time you have treatment.

There are different types of mask made from different materials, but you can breathe easily in them, though some people do find wearing it claustrophobic.

Images reproduced with the kind permission of Cambridge University Hospitals NHS Foundation Trust.

What happens during radiotherapy treatment?

During treatment you will lie on a treatment couch wearing your mask, which will be attached to the couch. The radiographer will take a few minutes making sure you are positioned correctly, then will leave the room. They can see and hear you throughout the treatment. You can also hear and speak to them.

Some radiotherapy machines move around you during treatment; others will look more like a CT scanner. See our Scans for adults page.

How long does radiotherapy take?

Each treatment is called a 'fraction'. Each fraction can be between a few seconds to a few minutes. Your appointment, however, will be considerably longer, as medical staff will take time making sure you're in the right place.

The period of time over which your radiotherapy is spread varies from person to person, but it's common for it to last for around 4-6 weeks.

An example of a typical radiotherapy plan is treatment once a day, Monday to Friday, with a break at the weekends.

Before the treatment begins, your medical team will be able to tell you how many sessions you'll need, how often and over what period. They'll also be able to give you a guideline for how long each visit to the hospital should take.

Why is the treatment given in several small doses rather than one dose?

The full dosage of radiation is carefully calculated, depending partly on the size, type and location of the tumour. It is then divided into fractions for two reasons:

  • The sensitivity of a cell to radiation depends on where it is in its growth cycle. By giving radiotherapy in several doses, it makes sure that the tumour cells will receive radiation whenever they are in their most sensitive stage
  • To allow healthy cells to recover between treatments. Cells that grow and divide quickly (tumour cells) are much more sensitive to radiation than non-dividing, resting, normal cells. Having a gap between doses gives the normal cells time to recover while still causing damage to the tumour cells.

Will the treatment be painful?

No, you can't feel radiotherapy nor is there any heat from it. The machine can be quite noisy though.

Will I need to stay in hospital for radiotherapy treatment?

Generally, you'll be given radiotherapy as an outpatient, which means going into the hospital for each fraction, after which you can go home.

A stay might be needed if you are also receiving chemotherapy, or if you are unwell.

What happens after radiotherapy treatment?

Following treatment, you'll have regular check-up appointments to monitor the effects of the radiotherapy on your tumour and any side-effects you may get.

Are there any side-effects?

It is likely that you will experience some side-effects. Most will be temporary and gradually fade, usually within 6 - 12 weeks after treatment has finished.

Radiotherapy works because it does the greatest damage to rapidly dividing cells, such as tumour cells. However, it can also affect any normal cells within the treatment area, particularly those which also divide rapidly.

Rapidly dividing cells include skin cells, cells lining the mouth and the digestive tract, plus blood cells in the bone marrow. These areas, therefore, tend to have the most common side-effects.

Side-effects will depend on the dose and length of treatment you have, and will differ according to the area of the brain that has received radiotherapy.

Common side-effects of radiotherapy include:

  • tiredness
  • hair loss
  • skin sensitivity – take care in the sun
  • feeling nauseous or reduced appetite
  • worsening of symptoms - due to temporary swelling in the treatment area
  • increased risk of infection, bruising and nosebleeds - caused by a slowing of blood cell production.

These effects are usually temporary.

You are not radioactive after treatment and are safe to be around people, including children.

Will I need to give up work?

It is likely that you will have to take some time off work during treatment and for a short time afterwards. Side-effects, such as tiredness and nausea, may mean you need a longer period of time off work.

Our Employment resources provide help and information on how to approach your employer about your diagnosis and how they can support you through this time.

Will there be any long-term effects of radiotherapy?

The way radiotherapy is given is designed to limit the chance of permanent side-effects and very few people develop long-term difficulties. Some side-effects can develop later in life.

Such difficulties include:

  • cognitive impairment e.g. memory issues
  • visual effects e.g. cataracts
  • hormonal effects e.g. affecting growth, weight, sleep or body temperature
  • developing a second tumour.

Some side-effects can develop months or even years later.

However, the risks of having radiotherapy are far outweighed by the benefits.

Other brain tumour treatments


Chemotherapy can be used as a treatment on its own, or it may be used with or after surgery or radiotherapy.


Steroids are sometimes given to help with symptoms as part of brain tumour treatment.

Brain tumour treatments

Find out more about the different brain tumour treatments available.

Help and support

If you or a loved one has been diagnosed with a brain tumour, we offer a range of support, including a phone line, private Facebook groups and information events. Find out more.

We've also got information and advice on living with a brain tumour.


Wigs and other headwear

Information about free wigs or where to buy wigs and other headwear can be found in our downloadable factsheet below.

Page last reviewed: 05/2018

Next review due: 05/2021

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