Radiation Oncology embraces all aspects of research that influences on the treatment of cancer using radiation. The field of radiation oncology covers the integration of radiation therapy into multimodal treatment approaches. External Beam radiotherapy is delivered outside the body. This includes directing high-energy radiation beams at the area being targeted within the body using various radiotherapy machines. Brachytherapy is radiation applied directly into the target. It is highly effective because the radiation is concentrated on the disease rather than healthy surrounding organs. Radioimmunotherapy (RIT) uses an antibody with specificity for a tumor- associated antigen labeled with a radionuclide to deliver cytotoxic radiation to a tumor cell. Systemic radiation therapy uses radioactive drugs to treat cancer systematically, in which the radioactive substance travels through the blood stream to reach cells all over the body.