During external beam radiation therapy, a beam of radiation is directed through the skin to destroy the cancer cells. To minimize side effects, the treatments are typically given five days a week for a number of weeks.

External beam radiation is similar to having an X-ray taken. The procedure is painless. The most common type of machine used to deliver external beam radiation therapy is called a linear accelerator, sometimes called a “linac.” It produces a beam of high-energy X-rays or electrons. Using sophisticated treatment planning software, your radiation oncology treatment team plans the size and shape of the beam, as well as how it is directed at your body, to effectively treat your tumor while sparing the normal tissue surrounding the cancer cells.

Several special types of external beam therapy are highlighted on the pages linked below. These are used for particular types of cancer, and your radiation oncologist will recommend one if it will help you.

• Three-Dimensional Conformal Radiation Therapy (3D-CRT)
• Intensity Modulated Radiation Therapy (IMRT)
• Image Guided Radiation Therapy (IGRT)
• Stereotactic Radiotherapy