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.