Radiation oncology is a medical specialty that uses radiation to treat cancer and other diseases. It involves using high-energy radiation, such as X-ray beams, to damage and destroy cancer cells, or to relieve symptoms caused by cancer.

Radiation oncologists are doctors who specialise in this field and oversee the treatment plan for patients undergoing radiation therapy.

Radiation therapy works by damaging the DNA in cancer cells. When the DNA is damaged beyond repair, the cells stop dividing and eventually die. It can take several treatments before DNA is damaged enough for cancer cells to die. For this reason, radiation therapy is often given as a course of treatment over several days or weeks.