Radiation therapy (or radiotherapy) is the medical use of ionizing radiation as part of cancer treatment to control malignant cells (not to be confused with radiology, the use of radiation in medical imaging and diagnosis).
Radiotherapy may be used for curative or adjuvant cancer treatment. It is used as palliative treatment (where cure is not possible and the aim is for local disease control or symptomatic relief) or as therapeutic treatment (where the therapy has survival benefit and it can be curative).
Radiotherapy is used for the treatment of malignant tumors (cancer), and may be used as the primary therapy.
It is also common to combine radiotherapy with surgery, chemotherapy, hormone therapy or some mixture of the three.
Most common cancer types can be treated with radiotherapy in some way.
The precise treatment intent (curative, adjuvant, neoadjuvant, therapeutic, or palliative) will depend on the tumour type, location, and stage, as well as the general health of the patient.
See Wikipedia, Radiation therapy.