OHSU

External-Beam Radiation Therapy

About external beam radiation

External beam radiation treats tumors and other conditions with powerful energy beams. If you have external beam radiation, you usually have treatment every day for several weeks. Your treatment schedule will depend on your tumor and other factors.

Types of external beam radiation include:

  • 3D conformal radiation therapy
  • Intensity-modulated radiation therapy
  • Total body radiation therapy
  • Calypso radiation therapy
  • RapidArc
  • Stereotactic radiosurgery and stereotactic body radiation therapy
  • Image-guided radiation therapy

During treatment, your body is placed so radiation beams reach the tumor. The radiation beam can also be shaped to give different doses to different areas of your body. Imaging scans, such as magnetic resonance imaging (MRI) and computerized tomography (CT) scans, can track radiation during treatment.

Your doctor makes a plan before you start external beam radiation therapy. The treatment reaches as much of the tumor as possible while avoiding healthy tissue.

If you have external beam radiation, your skin might be marked to show where the radiation will go. New computer techniques help determine the best place to give radiation.