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Reducing Radiation from Medical X-rays


FDA works to reduce radiation doses to the public while preserving image quality for an accurate exam by

  • establishing performance standards for radiation-emitting products, recommending good practices, and conducting educational activities with health professionals, scientists, industry, and consumers to encourage the safe use of medical X-rays and minimize unnecessary exposures
  • working with professional groups and industry to develop international safety standards that build dose-reduction technologies into various procedures and types of radiological equipment
  • working with states to help them annually inspect mammography facilities, test mammography equipment (X-ray machines to help detect breast cancer), and ensure that facilities adhere to the Mammography Quality Standards Act, which establishes standards for radiation dose, personnel, equipment, and image quality
  • monitoring industry technological advances that reduce radiation doses. Equipment manufacturers have already incorporated several advances to decrease the dose in newer machines that perform CT, which is considered the gold standard for diagnosing many diseases but also contributes greatly to the collective radiation dose to the U.S. population.
  • participating in "Image Gently," a national initiative to educate parents and health care professionals about the special precautions required for children who get X-rays. (Children are more sensitive to medical X-ray radiation than adults.)

Medical X-rays: How Much Radiation Are You Getting?

This table shows the radiation dose of some common medical X-ray exams compared to the radiation people are exposed to from natural sources in the environment. For example, the radiation exposure from one chest X-ray equals the amount of radiation a person is exposed to from their natural surroundings in 10 days.

The unit of measurement for an effective radiation dose is the millisievert (mSv). The average person in the United States receives a dose of about 3 mSv per year from naturally occurring radiation.

Three types of X-ray procedures are listed:

  • computed tomography (CT) generates a three-dimensional image of part of the body
  • radiography generates a two-dimensional image
  • mammography is radiography of the breast

For this procedure:

Your effective
radiation dose is:

Comparable to natural background radiation for:

Abdominal region:

Computed Tomography (CT)-Abdomen

10 mSv

3 years

Computed Tomography (CT)-Body

10 mSv

3 years

Radiography-Lower GI Tract

4 mSv

16 months

Radiography-Upper GI Tract

2 mSv

8 months





0.001 mSv

Less than 1 day


Computed Tomography (CT)-Chest

8 mSv

3 years


0.1 mSv

10 days

Women's Imaging:




0.7 mSv

3 months

Chart Copyright © 2009; Courtesy: American College of Radiology and Radiological Society of North America


For more information about topics for your health, visit the FDA Consumer Information Center (

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