ABSTRACT
INTRODUCTION Radiotherapy (radiation oncology) refers to the clinical specialty of medicine in which ionizing radiation, either alone or combined with other modalities, is used to treat cancer. The radiation oncologist is a highly specialized clinician whose training spans the entire spectrum of malignant disease and who requires an in-depth knowledge of the biologic and physical basis of radiation therapy as well as a fundamental knowledge of the natural history of human malignancy. On rare occasions radiotherapy is used to treat benign conditions, e.g. pituitary adenomas, pterygium, or to prevent hypertrophic bone formation following hip replacement. Radiotherapy is the most important non-surgical therapy and is used to treat approximately one-half of all common cancers; it may be used with either curative or palliative intent.
