Cancers in the head and neck are often quite small. This means that if radiotherapy is given it has be very precise to make sure that exactly the right spot is treated.

Usually for radiotherapy treatments patients are asked to to lie still for the few minutes whilst the treatment is in progress. But with head and neck tumours even a tiny movement during this time could affect the accuracy of the radiotherapy.

For this reason masks are often used for people having treatment for these tumours. The mask is a plastic shell or mesh which fits over the part of the face or throat which is being treated. When the patient is lying on the bed under the radiotherapy machine the mask is then fixed to the bed, for the few minutes of the treatment. This makes sure that everything is in exactly the right position for the treatment and that there is no possibility of any movement of the area being treated whilst the radiotherapy is given.

The masks (also sometimes called moulds or casts) are made individually for each patient so that they fit precisely and comfortably. Making, and wearing, the mask is not painful although it does often feel a bit strange and can take a bit of getting used to.

The mask is only needed for the few minutes of each radiotherapy treatment and does not have to be worn at other times.

As well as head and neck cancers, masks are sometimes used for brain tumours and other cancers where very precise treatment to a small area is needed.