What is radiotherapy?
Radiotherapy is the use of high-energy rays, usually x-rays and similar rays (such as electrons) to treat disease. It works by destroying cancer cells in the area that's treated.
Although normal cells can also be damaged by radiotherapy, they can usually repair themselves, but cancer cells can’t.
Radiotherapy is always carefully planned so that it avoids as much healthy tissue as possible. However, there will always be some healthy tissue that’s affected by the treatment and this will cause side effects.
Ways of giving radiotherapy
There are two ways of giving radiotherapy: external beam radiotherapy (also known as external radiotherapy) and internal radiotherapy.
External radiotherapy is given from outside the body usually using high-energy x-rays.
Internal radiotherapy is given from a radioactive material placed within the body.
This may be:
a solid radioactive material that is put close to, or inside, the tumour. This is known as brachytherapy.
a liquid source of radioactive material called a radioisotope. This is given as an injection into a vein or taken as a liquid or capsule by mouth. This is known as radioisotope therapy or radionuclide therapy.
Whether you have external or internal radiotherapy will depend on the type of cancer you have and where it is in the body. Some cancers are treated with both external and internal radiotherapy.