Radiotherapy is the use of high energy x-rays and similar rays (such as electrons) to treat disease.

Since the discovery of x-rays over one hundred years ago, radiation has been used more and more in medicine, both to help with diagnosis (by taking pictures with x-rays), and as a treatment (radiotherapy). While radiation obviously has to be used very carefully, doctors and radiographers have a lot of experience in its use in medicine.

Many people with cancer will have radiotherapy as part of their treatment. This can be given either as external radiotherapy from outside the body using x-rays or from within the body as internal radiotherapy.

Radiotherapy works by destroying the cancer cells in the treated area. Although normal cells can also be damaged by the radiotherapy, they can usually repair themselves.

Radiotherapy treatment can cure some cancers and can also reduce the chance of a cancer coming back after surgery. It may be used to reduce cancer symptoms.

Some people find that the side effects are very mild and that they just feel tired during their course of radiotherapy treatment.