Radiotherapy treats cancer by using high-energy rays which destroy the cancer cells, while doing as little harm as possible to normal cells. Radiotherapy may sometimes be given to the head (cranial therapy).

Radiotherapy is given in the hospital radiotherapy department. The course of treatment is usually in 8–10 sessions from Monday to Friday over two weeks, with a rest at the weekend. Your doctor will discuss your treatment with you in detail beforehand.

If you need to have high-dose treatment with stem cell support you may have a special form of radiotherapy called total body irradiation, or TBI. Radiotherapy is given to the whole body to destroy the bone marrow cells.

To make sure that the radiotherapy is as effective as possible, it has to be planned carefully. The first step is to make sure that you lie in exactly the same position for each treatment. On your first few visits to the radiotherapy department you will be asked to lie under a large machine called a simulator, which takes x-rays of the area to be treated. Sometimes a CT scanner may be used for the same purpose.

For cranial radiotherapy you may be fitted with a special clear plastic mask which is moulded to the exact size of your head and neck. This can be attached to the treatment couch and makes sure that your head stays in the correct position. Marks are made on the mask to show the treatment area. We can send you information about radiotherapy masks.

If you are not wearing a mask for treatment, marks will be drawn on your skin. This helps the radiographer, who operates the machine and gives you your treatment, to position you accurately and to show where the rays are to be aimed. These marks must stay visible throughout your treatment but they can be washed off once your treatment is over. Sometimes, you may have tiny permanent marks (like tattoos) on your skin. These will only be made with your permission. At the beginning of your radiotherapy you will be given instructions on how to look after your skin in the area being treated.

Treatment planning is a very important part of radiotherapy and may take a few visits. The treatment is planned by a doctor who specialises in radiotherapy (a clinical oncologist).

Before each session of radiotherapy the radiographer will position you carefully on the couch and make sure that you are comfortable. During your treatment, which only takes a few minutes, you will be left alone in the room but you will be able to talk by intercom to the radiographer, who will be watching you from the next room. Radiotherapy is not painful but you have to lie still for a few minutes while the treatment is being given.

Radiotherapy can cause general side effects such as feeling sick (nausea) and tiredness. When radiotherapy is given to the head it can cause specific side effects such as severe tiredness and drowsiness (somnolence), which usually appear a couple of weeks after your treatment begins and may last for a few weeks.

Hair loss

If you have radiotherapy to the head or to the testes, the hair in these areas will fall out. This is only temporary and it will usually grow back once your treatment is over, but it may not be as thick as it was before.

Feeling sick

Nausea can usually be effectively treated by anti-sickness drugs (anti-emetics), which your doctor can prescribe. If you don’t feel like eating, you can replace meals with nutritious high-calorie drinks. These are available from most chemists and can also be prescribed by your GP.

Our section on eating well has some helpful hints on how to eat well when you are feeling ill.

Tiredness

As radiotherapy can make you tired, try to get as much rest as you can.

All these side effects should disappear gradually once your course of treatment is over, but it is important to let your doctor know if they continue.

Radiotherapy does not make you radioactive and it is perfectly safe for you to be with other people, including children, throughout your treatment.

Our section on radiotherapy gives more details about this treatment and its side effects.