Radiotherapy uses high-energy rays to destroy cancer cells while doing as little harm as possible to normal cells. Radiotherapy only treats the area of the body that the rays are aimed at. It is often given in combination with chemotherapy. This is called chemoradiation. Chemotherapy makes cancer cells more sensitive to radiotherapy.
Radiotherapy does not make you radioactive. It is safe for you to be with other people, including children, throughout your treatment.