Making a radiotherapy mask

Radiotherapy is the use of high-energy x-rays (and other rays) to treat cancer. It’s important to lie still during treatment so that rays can be aimed very precisely at the right area of the body. This is even more important during radiotherapy to treat cancer in the head and neck area or brain tumours. To help with this, you wear a radiotherapy mask. 

A mould technician or radiographer makes the mask. One technique uses wet plaster bandages to make the mould, and the finished mask is made of perspex. The other technique uses mesh plastic, which is moulded to fit your face. Once the mask is ready, you may need to visit the hospital for adjustments. Your treatment may also be planned during this appointment, although it can take more than one visit.

When you have the radiotherapy, you’ll be lying on a firm couch (sometimes called a table) below the radiotherapy machine. The mask will be placed on your face and fixed to the table. Treatment can take 10–20 minutes and isn’t painful. 

What is a radiotherapy mask?

Radiotherapy is the use of high-energy x-rays (and other rays) to treat cancer. Radiotherapy has to be aimed very precisely to make sure that exactly the right area of the body is treated each time.

It's important to lie still while the treatment is in progress. This is because any movement could change the area that gets treated.

When you have radiotherapy to treat tumours in the head and neck area or brain tumours, it is even more important to be as still as possible. To help with this, you wear a radiotherapy mask during your treatment. This is sometimes called a mould, a head shell or a cast.

Once the mask is fitted, it is fixed to the radiotherapy treatment table. This holds your head and neck in exactly the right position for the treatment.

Wearing a mask reduces the possibility of any movement while you’re having radiotherapy. You only wear the mask during the planning procedures and during the treatment itself. Treatment usually takes about 10–20 minutes at a time each day. You’ll wear the same mask for planning and for treatment. You won’t have to wear the mask at any other time.


How a radiotherapy mask is made

You may need a dental check-up before your mould room appointment. If some of your teeth are unhealthy, you may need to have them removed before you start treatment. This is usually done before the mask is made to take account of any changes in shape to your head.

If you have a beard, you’ll need to trim it or shave it off before the mask is made. You will also need to have your hair cut before the mask is made and not make significant changes to your hairstyle during treatment. This is to ensure that the shape of your head stays the same throughout your treatment. If the shape of your head changes, a new mask will need to be made. This can delay treatment.

A mould technician or radiographer will make the mask in the mould room of the radiotherapy department. The process of making the mask can vary slightly between hospitals but it usually takes about 30 minutes. One technique uses wet plaster bandages to make the mould, and the finished mask is made of perspex. The other technique uses a type of mesh plastic, which is moulded to fit the shape of your face.


Perspex mask

If you're having a perspex mask, you may be given a swimming cap or some other covering to protect your hair from the mould mixture.

Strips of plaster of Paris being applied to the face to make a mould
Strips of plaster of Paris being applied to the face to make a mould

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Firstly, the mould technician will apply a cool cream or gel to your face. They then put strips of plaster of Paris bandage on top of this. They’ll leave holes around your nose and mouth, so you’ll still be able to breathe easily. 

Plaster of Paris gets warm as it sets. This is normal but it may feel uncomfortable. Don’t worry – it won’t burn you. The plaster of Paris takes about five minutes to set, and the mould is then taken off. A perspex mask is then made from this mould.

A finished perspex mask
A finished perspex mask

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Mesh plastic mask

This technique uses a type of plastic mesh that becomes soft and pliable when heated in warm water (thermoplastic). 

It is put onto your face so that the plastic gently moulds to fit your face exactly. It feels a little like a warm flannel. The mask has many holes in it so you’ll be able to breathe easily. 

The mesh takes a few minutes to be moulded and become hard. The mask is then taken off and is ready to be used when you have your treatment.


A plastic mesh mask
A plastic mesh mask

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Treatment planning

Once the mask is ready, you may need to visit the mould room again so that adjustments can be made to position the mask correctly on the radiotherapy treatment table.

Your treatment may also be planned during this visit. Treatment planning ensures that the radiotherapy is aimed very precisely at the cancer. You’ll be positioned on a machine called a simulator or on a CT scanner. This helps the radiographer plan the exact position you need to be in. Sometimes scans or x-rays are needed to help with planning.

The doctor or radiographer may make a few ink marks on the mask. You may also have a permanent mark made on your chest. This involves making a small scratch in the skin with a needle and some ink. These marks make it easier to position you correctly each time you come in for treatment. Radiotherapy planning can take more than one visit.

When you have the radiotherapy, you’ll be lying on a table below the radiotherapy machine. The mask will be placed on your face and fixed to the table so your head doesn’t move during the radiotherapy. The mask should be tight but not uncomfortable. If it’s uncomfortable, tell the staff who can see if they can adjust it. Treatment can take 10–20 minutes and is not painful. The staff will be close by to answer any questions you may have. You may find it useful to bring some calming music or a relaxation podcast to play during your treatment if you feel at all claustrophobic.

Back to External beam radiotherapy explained

What is external beam radiotherapy?

You may have external beam radiotherapy if it isn’t possible to remove all the thyroid tumour, there’s a high risk or it coming back or it’s spread to other parts of the body.

After treatment

It can take time for your body to recover after finishing treatment. Advice and support is always available.