External-Beam Radiation Therapy

External-beam radiation therapy (EBRT) is the most common type of radiation treatment used to treat cancer. Radiation is delivered from a source outside the body and directed at the tumor. Many cancers may be treated with this type of therapy, such as head and neck, breast, lung, colon and prostate.

Types of external-beam radiation include:

  • Three-dimensional conformal radiation therapy (3D-CRT)
  • Intensity-modulated radiation therapy (IMRT)
  • Stereotactic body radiation therapy (SBRT)
  • Adaptive radiation therapy (ART)
  • Gamma Knife
  • Proton beam therapy

EBRT is commonly delivered using images to target the tumor or nearby normal organs. Image-guided radiation therapy (IGRT) can be with x-ray, CT or MR imaging and can track static anatomical position or real time tumor motion.