External Beam Radiation Therapy

External beam radiation therapy involves a series of daily outpatient treatments that accurately deliver radiation to the area needing therapy. The radiation beam usually comes from a machine called a linear accelerator.

• Before beginning treatment, you will be scheduled for a simulation to map out the area to be treated. This will involve having X-rays and/or a CT scan. Landmarks placed on your skin (often tiny tattoos) allow the radiation therapists delivering your treatments to precisely position you each day.
• To minimize side effects, the treatments are given gradually over about five to six weeks, five days a week (Monday through Friday). This allows your doctors to get enough radiation into your body to kill the tumor cells while giving healthy cells time to recover each day.
• Technical terms that may be mentioned for cancer treatments include three dimensional conformal radiation therapy (3-D CRT), intensity modulated radiation therapy (IMRT) or image guided radiation therapy (IGRT). Your radiation oncologist can provide more information about these different techniques.