Image-guided radiation therapy (IGRT) is a method of radiation therapy that incorporates imaging techniques during each treatment session.

Radiation therapy uses high-energy beams of radiation to control cancer and noncancerous tumors. By adding detailed images, IGRT ensures the powerful radiation is narrowly focused at the treatment area.

When undergoing IGRT, high-quality images are taken before each radiation therapy treatment session. IGRT may make it possible to use higher doses of radiation, which increases the probability of tumor control and typically results in shorter treatment schedules.

IGRT is the standard of care for radiation therapy treatment. It's used to treat all types of cancer.

Mayo Clinic's approach

Why it's done

IGRT is used to treat all types of cancer, but it's particularly ideal for tumors and cancers located very close to sensitive structures and organs. IGRT is also useful for tumors that are likely to move during treatment or between treatments.

IGRT is used as part of radiation treatment plans because it offers:

  • Accurate delivery of radiation
  • Improved definition, localization and monitoring of tumor position, size and shape before and during treatment
  • The possibility of higher, targeted radiation dosage to improve tumor control
  • Decreased radiation exposure to normal tissue surrounding the tumor

What you can expect

If you undergo IGRT, your treatment team may choose one or more imaging types to precisely locate the tumor and sensitive organs. IGRT may involve a variety of 2-D, 3-D and 4-D imaging techniques to position your body and aim the radiation so that your treatment is carefully focused on the tumor in order to minimize harm to healthy cells and organs nearby.

During IGRT, imaging tests are done before, and sometimes during, each treatment session. Your radiation therapy team compares these images to ones taken previously to determine if your tumor has moved and adjust your body and your treatment to target your tumor more precisely.

Image-guided radiation therapy (IGRT) care at Mayo Clinic

Nov. 09, 2017
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  2. Jaffray DA. Image-guided radiotherapy: From current concept to future perspectives. Nature Reviews Clinical Oncology. 2012;9:688.
  3. Image-guided radiation therapy (IGRT). RadiologyInfo.org. http://www.radiologyinfo.org/en/info.cfm?pg=igrt. Accessed Oct. 10, 2017.
  4. Accredited facility search. American College of Radiology. http://www.acraccreditation.org/accredited-facility-search. Accessed Oct. 20, 2017.
  5. Fong de los Santos LE (expert opinion). Mayo Clinic, Rochester, Minnesota. Oct. 20, 2017.


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Image-guided radiation therapy (IGRT)