Radiotherapy uses high-energy rays to destroy cancer cells. It can be used to treat cancerous tumours and some benign (not cancer) or very slow-growing tumours. You will only have radiotherapy to the part of your body that needs to be treated.  

Radiotherapy machine

First, you will meet a doctor who specialises in radiotherapy, called a clinical oncologist. They will talk to you about your treatment and the possible side effects.  

You will have radiotherapy at a cancer treatment centre. If you do not live near a main cancer treatment centre, you might need to travel for your treatment. There will be a separate area in the cancer treatment centre where you will be given radiotherapy.  

Staff called radiographers give you the treatment. They will explain exactly what is involved and how any side effects can be managed. You will get lots of support. Tell the radiotherapy team if there is anything that is worrying you about the treatment.  

Radiotherapy can be used to cure a cancer. This is called radical radiotherapy. You will usually have it over several weeks. Radiotherapy is sometimes given in combination with surgery or chemotherapy.  

Sometimes radiotherapy is used to relieve symptoms such as pain. In this situation you usually only need one session or a short course of treatment.  

How is radiotherapy given?

Radiotherapy can be given from outside or inside the body.  

  • External radiotherapy is given from outside the body – this is the most common way radiotherapy is given. 
  • Internal radiotherapy is given from inside the body. The doctor may place a tube containing a radioactive substance in the area of the cancer. Or they may give you a drink or capsule of radioactive iodine to treat some thyroid cancers. 

Most people have radiotherapy as an outpatient. But sometimes you might be in hospital while you have it. This could be because you are having other treatments as well and need looking after.  

You usually have radiotherapy as short treatment sessions. You will probably have a treatment session every day from Monday to Friday. You will then have a break at the weekend.  

Your specialist doctor will tell you how many weeks your radiotherapy will last. This is known as your course of radiotherapy. It may last for several weeks.  

Some types of specialised radiotherapy are given in different ways.  

Radiotherapy from outside the body does not make you radioactive. You do not need to worry that you will harm anyone during your treatment. 

Planning your radiotherapy treatment

Your specialist doctor plans your radiotherapy carefully. This is to make sure the treatment works well and causes as little damage as possible to normal cells nearby. You might have to go to the radiotherapy department a few times to plan your treatment.  

You will have a planning CT scan of the area to be treated. This helps your doctor plan: 

  • the exact dose of radiotherapy to give you 
  • the position of the radiotherapy beams.  

During the scan, you lie still in the same position that you will be in for your radiotherapy. Planning can take a little while, but it is an important part of your treatment.  

Skin markings 

You might have some small, permanent marks (tattoos) made on your skin. They are about the size of a pinpoint. They help the radiographer make sure you are in the right position for each session of radiotherapy. They will only make these marks with your permission. If you are worried about having them done, tell your radiographer.  

Radiotherapy masks 

If you are having radiotherapy to your head or neck, you will have a mask made before the planning CT scan. The mask keeps your head and neck in exactly the right position during your radiotherapy. You only need to wear it during radiotherapy planning and your sessions of radiotherapy. 

The mask is made of mesh plastic or a clear plastic (perspex). The mesh is warmed and put on to your face so that the plastic gently moulds to fit the shape of your head and neck. When it has moulded, the mask will feel hard. It usually takes about 30 minutes to make the mask, and it won’t hurt.  

You can breathe normally while the mask is on, and it shouldn’t feel uncomfortable. You might feel claustrophobic as it is on your face, but the radiotherapy team will talk to you about ways of coping with this.  

Having radiotherapy

Your radiographer will explain what will happen during treatment. At the beginning of each session, they will make sure you are in the correct position. You will need to lie still under the radiotherapy machine. Radiotherapy machines look like large x-ray machines.  

When everything is ready, your radiographer will leave the room. This is when you will have the radiotherapy. It only takes a few minutes. You can talk to the radiographer through an intercom or signal to them during the treatment. You can usually bring music to play if you want. 

Radiotherapy treatment is not painful. You will not see or feel it.  

During treatment, the radiotherapy machine may stop and move into a new position. This is so you can have radiotherapy from different directions. The machine does not normally touch you. 

Specialised types of external radiotherapy

Sometimes specialised types of external radiotherapy are used:

Stereotactic radiotherapy

Stereotactic radiotherapy (SRT) can be used to treat certain brain tumours. SRT uses many small beams of radiation that target the tumour. The beams cross over at the tumour. This means that the tumour gets a high dose of radiation and nearby areas only get low doses. This helps to reduce the side effects of treatment.  

SRT is sometimes called Gamma Knife™ or CyberKnife™ because of the names of the different machines used to give this type of treatment.  

You might only need one session of treatment. Or it might be given over several sessions of treatment. A session can take from about 15 minutes to a few hours, depending on the type of machine. Your radiotherapy team will tell you what to expect. 

You may need a mask or a head frame made to help keep you in position during treatment. Your radiotherapy team will talk to you about this and give you lots of support.  

Total body irradiation

Total body irradiation (TBI) is radiotherapy to the whole body. You may have TBI if you need a donor stem cell (allogeneic) transplant. It can be given as part of the treatment to get you ready to receive the donor’s cells.  

You may have TBI twice a day over several days, or as one or two sessions. You have it to the front and back of your body. Your radiotherapy team will explain everything and help you to change position when you need to.  

Proton therapy

Proton therapy uses protons rather than x-rays to treat a tumour. But it is given in a very similar way to standard radiotherapy. Treatment with proton therapy may cause less damage to surrounding healthy tissue and reduce the side effects of treatment.  

At the moment, for those with tumours that it is recommended are treated with proton therapy, treatment will either be at The Christie Hospital in Manchester, at University College London Hosptial, or in some cases you will travel abroad for treatment. This is paid for by the NHS.

Your specialist doctor will give you more information if they think proton therapy might be helpful for you.