What is external beam radiotherapy?

External beam radiotherapy is a treatment that uses high-energy beams to destroy cancer cells. The beams are given using equipment similar to a large x-ray machine. A radiographer operates the machine.

This type of radiotherapy may be used to:

  • treat and cure the cancer (curative or radical radiotherapy)
  • control symptoms caused by the cancer (palliative radiotherapy).

Before you have your radiotherapy, you may be asked to take off some of your clothes and wear a gown. The radiographers will use any marks on your skin (and on your mask, if you have one) to help you get into the correct position. They will make sure you are comfortable.

The radiographers will then leave the room. They will be able to see you and may be able to speak to you through an intercom. The treatment itself takes a few minutes and is not painful.

It’s normal to feel worried about having external radiotherapy. But don’t be afraid to talk to the radiotherapy staff about your worries – they’re there to help.

External radiotherapy

External radiotherapy is normally given as a number of short, daily treatments in the radiotherapy department. It is given using equipment similar to a large x-ray machine. Several different types of radiotherapy machines are used to give radiotherapy, but they all work in a similar way. One commonly used machine is called a linear accelerator (LINAC).

You usually have external radiotherapy as an outpatient. How many treatments you have will depend on the aim of the treatment.


Curative (radical) radiotherapy

Curative treatment usually involves having a course of treatments given once a day, often with a rest at the weekends. The treatment may last between 1–7 weeks. Each treatment is called a fraction.

Giving the treatment in fractions ensures that less damage is done to normal cells than to cancer cells. The damage to normal cells is mainly temporary, but this is what causes the side effects of radiotherapy.

Some people may have curative treatment:

  • more than once a day
  • every day for two weeks, including the weekends
  • three days each week – for example on Mondays, Wednesdays and Fridays
  • once a week for a number of weeks.

You can have curative treatment:

  • on its own
  • before or after surgery
  • before or after chemotherapy
  • at the same time as chemotherapy (chemoradiation).


Palliative radiotherapy

Palliative radiotherapy (for symptom control) may be used in a number of different situations. For example, you may have it to:

  • one or more bones, to help control pain caused by cancer spreading to the bones
  • the lungs, to reduce coughing caused by cancer in the lungs
  • help control bleeding caused by lung, bladder or skin tumours.

Palliative radiotherapy may involve only one or two sessions of treatment, but sometimes it can involve 10 sessions or more. When treatment is given in one or two sessions, it may cause slightly more short-term side effects, such as flu-like symptoms.


Treatment sessions

Usually, each radiotherapy appointment takes about 10–30 minutes, although you may be in the department for longer. The treatment itself only lasts a few minutes and most of the appointment is spent getting you into the correct position and doing checks.

Before your first treatment, the radiographers will explain to you what you’ll see and hear. It’s normal to feel anxious about having your treatment. But, as you get to know the staff and understand what’s going on, it usually becomes easier. The sight of large radiotherapy machines can be frightening, especially for children. You can talk to the staff about any fears or worries you have. The staff are there to help you and the more you understand your treatment, the more relaxed you’ll be.


Setting up

Before your treatment, you may be asked to take off some of your clothes (from the area of your body that needs treating) and to put on a gown. This is so the radiographers can easily get to the marks on your skin that show the treatment area.

When the radiographers are ready for you, they’ll position you carefully on the treatment couch and adjust its height and position. This is often called ‘setting up’ and may take a little while. Your radiographers will tell you how long it will take. The radiographers will use the marks on your skin (and on your mask, if you have one) to help get you in the same position you were in for your planning scan.

It’s important that you’re comfortable, as you have to lie as still as possible during the treatment. Let the radiographers know if you’re not comfortable. The room may be in semi-darkness while the radiographers are setting up.

Once you’re in the correct position, the radiographers will leave the room and you’ll be given your treatment. Your radiographers will tell you how long your treatment will take before you start. There will be a camera so they can see you from outside the room. Many treatment rooms also have an intercom, so the radiographers can talk to you while you have your treatment.

Someone being positioned for external radiotherapy
Someone being positioned for external radiotherapy

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During treatment

During each treatment, the radiographers will watch you from outside the room. If you are worried about anything, you can speak to them through the intercom and they will come in to help you. If there isn’t an intercom in the room, the radiographers will let you know how you can get their attention if you need to. They will also take care to protect your privacy so that nobody else can see you.

Some treatment rooms have CD or MP3 players so you can listen to music to help you relax during your treatment. If you’d like to listen to your own music, ask your radiographers if this is possible.

The treatment itself is painless. You may hear a slight buzzing noise from the radiotherapy machine while your treatment is being given.

The radiotherapy machine doesn’t normally touch you, although for some types of skin cancer it may press against your skin.

Most curative (radical) radiotherapy involves having treatment from several different directions. This means that, during your treatment, the radiotherapy machine will automatically stop and move into a new position before your treatment continues. This may happen several times and you’ll need to stay lying still. Occasionally, the radiographers will come into the treatment room to change the position of the machine.

During your treatment, the radiotherapy machine may take pictures (x-rays or CT scans) of the treatment area as part of the normal treatment process. These are taken to make sure the treatment is given accurately. They may be taken on the first day and again on other days. The radiographers will explain more about this to you.

Once your treatment session has finished, the radiographers will come back into the room and will help you off the treatment couch. You will then be able to get ready to go home or back to the ward.

External radiotherapy doesn’t make you radioactive. It’s perfectly safe for you to be with other people, including children, throughout your treatment. It’s also safe to have sex.

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