What is external beam radiotherapy?

External beam radiotherapy is given from a radiotherapy machine outside the body. The radiotherapy machine does not usually touch you. Treatment usually only takes a few minutes and is not painful.

This treatment is normally given as a number of short, daily treatments in a radiotherapy department. These are called treatment sessions or fractions. It is given using a machine that looks like a large x-ray machine or CT scanner.

You usually have external beam radiotherapy as an outpatient. The number of treatment sessions you have will depend on the type of cancer you have and the aim of the treatment. Your doctor, radiographer or nurse will explain the treatment plan to you.

What is external beam radiotherapy?

External beam radiotherapy is given from a radiotherapy machine outside the body.

This treatment is normally given as a number of short, daily treatments in a radiotherapy department. These are called treatment sessions or fractions. It is given using a machine that looks like a large x-ray machine or CT scanner. There are different types of radiotherapy machine. The most commonly used machine is called a linear accelerator (LINAC).

External beam radiotherapy
External beam radiotherapy

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You usually have external beam radiotherapy as an outpatient. The number of treatment sessions you have will depend on the type of cancer you have and the aim of the treatment. Your doctor, radiographer or nurse will explain the treatment plan to you. This includes how many treatment sessions you will have, and when you will have them.

Radiotherapy explained

Consultant Clinical Oncologist Vincent Khoo describes external beam radiotherapy, how it works, and what it involves.

Information about our videos

Radiotherapy explained

Consultant Clinical Oncologist Vincent Khoo describes external beam radiotherapy, how it works, and what it involves.

Information about our videos


Curative (radical) radiotherapy

The term radical radiotherapy is used when doctors are hoping to cure the cancer. It usually involves having several treatment sessions. This is called a course of treatment.

You usually have one session of radiotherapy a day, often with a rest at the weekends. Some radiotherapy departments give treatment at the weekend. This means you would have rest days during the week instead. For certain types of cancer, treatment is given up to 3 times a day.

The treatment may last between 1 and 8 weeks.

Giving the treatment in several sessions means that normal healthy cells have time to recover between treatments. You may have curative radiotherapy:

General information

Deanne sitting in a hospital waiting room reading with her young daughter. Deanne on treatment

'Afterwards they asked me if I wanted to keep the mask. I really didn't want to be anywhere near it.'


Palliative radiotherapy

Palliative radiotherapy may be used to help shrink the cancer and to control symptoms. For example, you may have it to help:

  • control pain caused by cancer that has spread to the bones
  • reduce coughing caused by cancer in the lungs
  • control bleeding caused by certain types of tumour.

If you are having palliative radiotherapy, you may have 1 to 2 sessions of treatment. Sometimes you may have a course of up to 10 to 15 sessions. For some types of brain tumour, it can be up to 30 sessions. How many treatment sessions you have depends on your situation and the type of cancer you have.


Having external beam radiotherapy

Treatment sessions

Usually, each radiotherapy appointment takes about 10 to 30 minutes, although you may be in the department for longer. The treatment itself usually only takes a few minutes. Most of the appointment is spent getting you into the correct position and checking your details.

Before your first treatment, the radiographers explain what you will see and hear. It is normal to feel a bit nervous about having your treatment. But, as you get to know the staff and understand what to expect, it usually gets easier. You can talk to the staff about any worries you have.

Positioning you for treatment

Before your treatment, the radiographer may ask you to change into a hospital gown. This is so they can easily reach the marks on your skin that show the treatment area.

The radiographers help you onto the treatment couch and position you carefully. They also adjust the height and position of the couch. They will talk you through what they are doing.

The radiographers look at the marks on your skin (or on your mask or mould, if you have one). This is to help get you in the same position you were in for your planning scan. They help you arrange your clothes or gown so that the area of your body being treated is bare. They are careful to protect your privacy so that nobody else can see you.

It is important that you are comfortable, as you have to lie as still as possible during the treatment. Let the radiographers know if you are not comfortable. The room may be quite dark to help the radiographers while they are getting you into the correct position.

Your radiographers will tell you how long your treatment will take. When you are in the correct position, they leave the room and you are given your treatment. There is a camera, so they can see you from outside the room. There is usually an intercom, so you can talk to them if you need to during your treatment.

During treatment

The radiotherapy machine does not usually touch you. But if you are having radiotherapy for some types of cancer, it may gently press against your skin.

The treatment itself is painless. You may hear a slight buzzing noise from the radiotherapy machine while you are having the treatment.

Some treatment rooms have music players, so you can listen to music to help you relax. If you would like to listen to your own music, ask your radiographers if this is possible.

Most curative (radical) radiotherapy involves having treatment from several different directions. To do this, the radiotherapy machine may move around you into different positions during your radiotherapy. This may happen several times and you will need to stay lying still. Sometimes, the radiographers will come into the treatment room during your treatment to change the position of the machine.

The radiotherapy machine may take pictures (x-rays or CT scans) of the treatment area during your treatment. They may be taken on the first day and again on other days. These pictures are used to help make sure the treatment is given accurately. They are not used to show how well treatment is working, as treatment takes time to work.

Once your treatment session has finished, the radiographers will come and help you off the treatment couch. It is important to wait until they tell you it is ok to move. Then you can get ready to go home, or back to the ward if you are having treatment as an inpatient.

External beam radiotherapy does not make you radioactive. It is safe for you to be with other people, including children, throughout your treatment. It is also safe to have sex. We have more information about relationships and sex.

I got used to the radiotherapy very quickly. After the first few sessions, it was fine. I knew what to expect and it wasn’t as scary as I thought.

Frances

Although you’re alone when it’s being given, the staff are watching and listening through it. I had three sessions lasting six minutes each, without pain and no immediate side effects.

Lynda

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