This treatment involves targeting the cancer with high energy radiation beams. This kills the cancer cells and stops them multiplying. This is used if surgery is not possible, for example, if the patient is too unwell or desperately does not want surgery. It may, however, be the preferred treatment of choice; for example, in lymphoma. This treatment is performed as an out-patient. This treatment is spit into fractions. This means the treatment is divided into smaller doses and spread out over a few days. This gives healthy cells in the body a chance to recover between treatments. If we are using radiation to treat the eyes or lymph nodes around the head and neck, then a special mask is usually made for patients. This mask is worn during treatment and helps aim the radiation at only the cancer cells. Although this helps prevent damage to healthy cells around the tumour, treatment may still cause loss of eyelashes, loss of pigmentation of the eyelids, and inflammation of the conjunctiva causing a watery eye.