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Radiotherapy moulds

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This page tells you about radiotherapy moulds and masks. There is information about


Radiotherapy moulds

You may need to have a mould or mask made for radiotherapy to certain parts of the body, such as your leg or arm or your head or neck. The mould is also called a shell. Moulds for the head or neck area are also called masks. 

Moulds keep the treatment area of your body still each time you have your radiotherapy. The radiographers may also make marks on them. The marks are used to accurately line up the radiotherapy machine for each treatment. It is very important that you are in exactly the same position each time. 

You may have the mould made in the mould room of the radiotherapy department or during your CT planning session. It takes between 10 to 60 minutes.


Preparing to make your radiotherapy mould

Moulds are normally made directly against your skin. You will need to wear clothing that you can easily take off from the area to be treated. You will also need to take off any jewellery from that area.

You may need to take off make up. It may be helpful not to wear any. Or you could take along make up removing items as well as new make up to apply afterwards.

If you have a lot of facial hair this can make if difficult to make a head and neck mask. The radiotherapy staff will advise you on any hair issues at your planning session.


Radiotherapy masks

For radiotherapy to your head or neck, you will need to wear a mask during your treatment and for your CT planning scan. 

Some types of mask are see through and others aren't. The mould keeps your head completely still. So your treatment will be as accurate as possible.

A mould technician or radiographer makes the mask in the mould room of the radiotherapy department or during your CT planning scan. There are 2 ways of making them. One way uses a plastic mesh that the technician moulds to the shape of your face and neck. The other way uses wet plaster bandages to make a perspex mask. 

The process can vary slightly between hospitals and usually takes around 30 minutes.


Mesh plastic mask

This technique uses a special kind of plastic heated in warm water so that it becomes soft and pliable. The technician puts the plastic on to your face so that it moulds to fit your face exactly. It feels a little like having a warm flannel put onto your face. You can still breathe easily, as the plastic won't cover your nose or mouth.

After a few minutes the mesh moulds and becomes hard. The technician takes the mask off. It is then ready for use. 

Mesh plastic mask used for radiotherapy for the head and neck area

The video below shows what happens when you have your mesh mask made:

View a transcript of the video showing what happens when you have your mesh mask made. The transcript opens in a new window.


Perspex mask

The technician may give you a swimming cap or some other covering to wear, to protect your hair from the mould mixture. Firstly, they apply a cool cream or gel onto your face. Then, they put strips of plaster of paris bandage on top of this. You will still be able to breathe, because they leave holes around your nose and mouth.

Plaster of paris gets warm while it is setting. This is normal and may make the process uncomfortable. It won't burn you though. The plaster takes about five minutes to set and the technician then removes it. They make a perspex mask from this mould.

The picture shows a perspex mask.


The mask fits snugly to your face and neck and has holes cut for your eyes, nose and mouth. It is ready to wear at your next visit.


The photo above shows how the mould fixes to the radiotherapy table while you are having treatment. It may feel strange and claustrophobic at first. You may need to wear it for between 15 to 45 minutes. Let the staff in the department know if you feel worried or anxious. They can make suggestions about what may help you to relax.


Arm or leg moulds

If you are having a mould for radiotherapy treatment to your arm or a leg, you have the same process as for a face mask. The mould room may also need to make a personalised leg or arm rest for you, as well as the mould.


More information on radiotherapy

Find out about

External radiotherapy

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Radiotherapy team

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Updated: 18 February 2016