What is external beam radiotherapy?

External radiotherapy uses a machine called a linear accelerator. It is like a big x-ray machine, which produces high-energy rays. A radiographer gives you the treatment in the radiotherapy department at the hospital. You have it as an outpatient once a day from Monday to Friday, with a rest at the weekend. Each session of treatment usually takes just a few minutes. A full course may last up to 5 to 6 weeks.

External radiotherapy is painless. It will not make you radioactive. It is safe for you to be around other people, including children and pregnant women.

Planning your radiotherapy

Your radiotherapy will be planned by your clinical oncologist with the support of a technical team. The planning is done to make sure the radiotherapy targets the area accurately and causes as little damage as possible to nearby tissue.

First planning visit

Your first planning visit will take 30 to 60 minutes. The staff in the radiotherapy department will explain what to expect. It is fine to ask as many questions as you need to. The staff will tell you beforehand if you need to prepare in any way. For example, you may be asked to drink plenty of water and to use a small enema. An enema is a liquid that empties the lower part of the bowel. Your team will explain how to use it.

You will usually have a CT scan of the area to be treated. This helps your doctor plan the precise area for your radiotherapy. Before your scan, you may be asked to remove some of your clothes and to wear a gown.

You may have an injection of dye into a vein when you have the CT scan. This allows particular areas of the body to be seen more clearly.

During your scan, you need to lie still on a hard couch. If you feel uncomfortable when the radiographers position you on the couch, let them know. They can make you more comfortable. This is important because, once you are comfortable, they will record the details of your position. You will need to lie in the same position on a similar couch for your treatment.

The information from the scan will be used by your radiotherapy team to work out the precise dose and area of your treatment. It can take up to two weeks to plan your treatment.

The radiographer will make some tiny tattoos on your skin. This may be a little uncomfortable while they are doing it. They will only do it your permission. The tattoos help the radiographers position you at each treatment session to make sure the rays are directed accurately.

Treatment sessions

At the beginning of each session, your radiographer will explain what you will see and hear.

Once you are comfortable, and in the correct position, they will ask you to keep as still as possible. The radiographers will leave the room for a few minutes while you have your treatment. There will be a camera so they can see you from outside the room. There is usually an intercom, so you can talk to them if you have any concerns during your treatment.

The radiotherapy machine does not touch you and the treatment is painless. You may hear a slight buzzing noise from it while you have your treatment.

Once your treatment session has finished, the radiographers will come back and help you off the treatment couch. You will then be able to go home or, if you are staying in hospital, back to the ward.

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