Planning your radiotherapy

Radiotherapy is carefully planned for each person by a team of experts.

Your radiotherapy team will explain what to expect. Your first planning visit usually takes between 30 to 60 minutes. Sometimes it may take more than 1 visit. You will have scans of the area to be treated. This helps the radiotherapy team decide the exact dose of radiotherapy and what area to treat.

During planning, the radiotherapy staff may make a small permanent mark (like a tattoo) on your skin. This is to show the exact place the radiotherapy should be given

You may need a mould or mask for your radiotherapy. These help you stay still in the correct position. Moulds are for a leg, arm, or other body part. You only need a mask if you are having radiotherapy to your head or neck. It fits tightly but it should not be uncomfortable. You only wear it for during your planning and while you are having the radiotherapy.

Planning your radiotherapy

Before you start your treatment, it needs to be planned. This is to make sure that the radiotherapy is aimed precisely at the cancer. This will also mean it causes the least possible damage to the surrounding tissue. Your radiotherapy team will plan your radiotherapy carefully.

Some people may need to have a mould or mask made before treatment planning (see below).

First planning visit

Your first planning visit usually takes 30 to 60 minutes, although it may take longer. Sometimes it may take more than one visit.

Your radiotherapy team tell you what to expect. They also tell you if there is anything you need to do to prepare. For example, you may be asked to follow a special diet or drink plenty of water.

It is important that you feel involved in your treatment. So, feel free to ask as many questions as you need to.

You will usually have a CT scan of the area to be treated. This helps plan the precise area for your radiotherapy. Before your scan, the radiographer may ask you to change into a hospital gown.

A CT scan takes lots of pictures from different angles to build up a 3D picture of the inside of your body. During the scan, you may have an injection of dye into a vein. This allows different areas of the body to be seen more clearly. You may also be asked to have a full or empty bladder for the scan.

Some people will also have an MRI scan or a PET scan. MRI scans use powerful magnets to give a very detailed picture of the area that needs treating. PET scans use low-dose radioactive glucose (a type of sugar) to measure the activity of cells in different parts of the body. Your healthcare team will tell you more about these scans.

During your scan, you need to lie still on a hard couch (sometimes called a table). Your head, arms and legs may be supported with moulded plastic, foam or rubber cushions. If you have a mould or mask, it will also be carefully fitted to help you lie still (see below).

If you feel uncomfortable, tell the radiographers so they can make you more comfortable. This is important. The radiographers record the details of your position. You need to be able to lie in the same position for your radiotherapy treatment.

The information from the scan is sent to a planning computer. Your radiotherapy team use this to work out the precise dose and area of your treatment.

The radiotherapy team measured and fitted the mask and did scans to work out exactly where they wanted to aim the radiotherapy.


Someone having a CT scan

Having a CT scan

A radiographer explains how a CT scan works, and Jyoti talks about her experience.

About our cancer information videos

Having a CT scan

A radiographer explains how a CT scan works, and Jyoti talks about her experience.

About our cancer information videos

Radiotherapy moulds and masks

You may need to have a mould or mask made before radiotherapy planning starts. This is to help you stay still and in the correct position during your radiotherapy. Moulds keep a leg, arm, or other body part still during planning and treatment. Masks may be used for people having radiotherapy to the brain, head or neck.

Moulds and masks are made of a plastic mesh. The mesh is warmed and put on to your face or other body part, so that the plastic gently moulds to fit the area being treated. Your mould or mask should fit tightly, but it should not be uncomfortable. The mesh takes a few minutes to harden. It is then taken off and is ready to be used when you have your treatment.

You may feel very nervous or claustrophobic if you have to wear a mask for treatment. But remember, you only wear it for short periods of time during planning and your radiotherapy. You can breathe normally while you are wearing it.

Most people cope well with the support of the radiotherapy team. If you are worried or uncomfortable, let them know so they can help you. Sometimes your doctor can give you medication to take before the treatment to help you relax. But this is not usually needed.

It was a very unusual experience. You had to lie really still while they put warm plastic on your face. And it moulded exactly to your features.


Skin markings

You may have markings made on your skin to help the radiographers position you accurately for treatment.

Usually, tiny permanent markings are made in the same way as a tattoo. The marks are the size of a pinpoint and are only made with your permission. It can be a little uncomfortable while they are being made, but it makes sure that the treatment is directed accurately. If you have a mould or mask, the marks may be made on this.

If you are concerned about having permanent marks, let your radiographers know. They can discuss other options with you.

Back to Radiotherapy explained

What is radiotherapy?

Radiotherapy uses high-energy rays to destroy cancer cells. This treatment is used to cure some types of cancer or to relieve symptoms.

Before your radiotherapy

Before you start radiotherapy, your team will explain what your treatment involves and how it may affect you.

Masks for radiotherapy

During most types of radiotherapy to the brain, head or neck, you wear a mask to help you keep still.

Your radiotherapy team

You will meet many different specialists from your radiotherapy team. You may see them before, during and after radiotherapy treatment.

After your radiotherapy

It can take time to recover from radiotherapy. Support is there if you have any problems.