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Radiotherapy moulds and masks

Find out about radiotherapy moulds and masks and about the process of making them.

About radiotherapy moulds and masks

You might need to have a mould or mask made before your radiotherapy. The mould is also called a shell. The shell keeps the treatment area of your body still each time you have your radiotherapy. So your treatment will be as accurate as possible.

You might need a shell for radiotherapy to your head or neck or to an arm or leg. Moulds for the head or neck area are called masks. 

Some types of mould are see through and others aren't. The radiographers might make marks on them. They use the marks 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 might have the mould made in the mould room of the radiotherapy department or during your CT planning session. It takes between 10 to 45 minutes depending on the type of mould.

Preparing for a mould or mask

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

You might 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.

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

There are 2 ways of making masks. One way uses a plastic mesh that the technician moulds to the shape of your face and neck. The other method uses wet plaster bandages to make a perspex mask. 

The process can vary slightly between hospitals.

Making a mesh plastic mask

A mould technician or radiographer makes the mask in the mould room of the radiotherapy department or during your CT planning scan.

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. 

Radiotherapy mask
A mesh mask

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

Making a perspex mask

The technician may give you a swimming cap or some other covering to wear, to protect your hair from the mould mixture.

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.

Photo showing a perspex mask
A perspex radiotherapy 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.

Photo showing the perspex mask fixed to the radiotherapy table
A perspex radiotherapy mask

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.

Last reviewed: 
18 Feb 2016
  • External Beam Therapy
    Peter Hoskin
    OUP Oxford, 30 Aug 2012

  • Practical Radiotherapy Planning Fourth Edition
    Ann Barrett, Jane Dobbs, Tom Roques
    CRC Press, 26 Jun 2009

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