Radiotherapy (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.

Radiotherapy uses controlled doses of high energy beams 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.

Before 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 three-dimensional image showing the precise location and shape of the tumour. This allows the tumour to be targeted more precisely.

Treatment mask

To make sure the radiotherapy is directed to the correct part of your brain, it is 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 breath easily in them, though some people do find wearing it claustrophobic.


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.

Each treatment is called a 'fraction'.

How long does the treatment take?

Each fraction can be between a few seconds to a few minutes. 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.

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 ensures 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)

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 my 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.

Are there any side-effects?

It is likely that you will experience some side-effects. Most will be temporary and gradually fade once the treatment has finished. Others can be long-term or even permanent.

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 include:

  • Tiredness
  • Hair loss
  • Feeling nauseous
  • Skin sensitivity – take care in the sun

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.

Precisely when you go back is your decision. There are organisations that can help you back to work.

After treatment

Long-term effects

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

However, 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
  • Cancer

The risks of having radiotherapy are far outweighed by the benefits.

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