Radiotherapy means the use of radiation, usually x-rays, to treat cancer. You might have radiotherapy from inside the body, called internal radiotherapy. Or external radiotherapy, which is from outside the body.
Radiotherapy can be used to try to cure cancer, reduce the chance of cancer coming back or to help relieve symptoms. You might have it by itself or with other treatments, such as chemotherapy or surgery.
Nearly 50 out of 100 (50%) people have radiotherapy at some point during their cancer treatment.
Most types of radiotherapy use photons. But you might have electrons or more rarely protons. Your doctor will decide which type you need.