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U.S. Department of Health and Human Services

Radiation-Emitting Products

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Questions & Answers: Initiative to Reduce Unnecessary Radiation Exposure from Medical Imaging

What is the Initiative to Reduce Unnecessary Radiation Exposure from Medical Imaging, and why is FDA launching it?

The Initiative to Reduce Unnecessary Radiation Exposure from Medical Imaging is a collaborative effort aimed at minimizing the risks associated with exposure to ionizing radiation in certain types of medical imaging procedures, while supporting the benefits these exams can provide. The initiative focuses on the three types of procedures that are the greatest contributors to the U.S. population’s total radiation exposure from medical imaging: computed tomography (CT), fluoroscopy, and nuclear medicine studies.

CT, fluoroscopy, and nuclear medicine procedures have led to improvements in the diagnosis and treatment of numerous medical conditions. At the same time, these types of exams expose patients to ionizing radiation, which may elevate a person’s lifetime risk of developing cancer.

When used appropriately, the medical benefits these exams can provide generally outweigh the risks. However, if proper precautions are not taken, patients can be exposed to radiation without clinical need or benefit. A balanced public health approach seeks to make sure that each patient will get the right imaging exam, at the right time, with the right radiation dose.

Through this initiative, FDA and our partners in the Federal government and the healthcare professional community will take steps to reduce unnecessary radiation exposure from medical imaging by promoting the safe use of medical imaging devices, supporting informed clinical decision making, and increasing patient awareness.

For more information about the initiative, see the White Paper for the Initiative to Reduce Unnecessary Radiation Exposure from Medical Imaging.

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What types of medical procedures are addressed by the Initiative to Reduce Unnecessary Radiation Exposure from Medical Imaging?

The Initiative to Reduce Unnecessary Radiation Exposure from Medical Imaging focuses on the three types of imaging studies that account for the largest share of the U.S. population’s total annual exposure to radiation from medical imaging: computed tomography (CT), fluoroscopy, and nuclear medicine.

In addition to this initiative, FDA is also exploring steps we can take to improve patient safety in radiation therapy.

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What is the timeframe for the actions FDA is taking as part of the Initiative to Reduce Unnecessary Radiation Exposure from Medical Imaging?

FDA and our partners have already begun to undertake some of the efforts outlined in the White Paper. As a first step toward establishing requirements for manufacturers of CT and fluoroscopic devices, FDA intends to solicit input from our external constituencies through a public meeting on March 30-31, 2010.

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What is ionizing radiation?

Radiation is a term for energy waves or particles that travel through a medium, like light or radio signals through the air. Ionizing radiation has enough energy to potentially cause damage to DNA. X-rays are a type of ionizing radiation. People are exposed to some background level of naturally occurring ionizing radiation every day.

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Do all medical imaging procedures use ionizing radiation?

No. Different types — or modalities — of medical imaging procedures use different technologies and techniques.

Ultrasound imaging (also called sonography) uses high-frequency sound waves to view soft tissues such as muscles and internal organs. Magnetic resonance imaging (MRI) uses radio waves and magnetic fields to produce images.

Unlike ultrasound and MRI, projection radiography (commonly called standard x-ray), CT, fluoroscopy, and nuclear medicine procedures all use ionizing radiation to generate images of the body. These imaging procedures use different amounts of ionizing radiation. Standard x-ray procedures, including chest X-rays and mammography, use relatively low amounts. CT scans, nuclear medicine studies, and fluoroscopy use higher amounts of ionizing radiation and account for most of the radiation patients in the U.S. are exposed to in a given year.

For more information about different types of medical imaging procedures, see FDA’s Medical Imaging page.

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How often are patients who undergo medical imaging exposed to unnecessary radiation?

We do not know. Unnecessary radiation exposure may be the result of performing an exam without appropriate clinical justification, or the use of more radiation than needed to create a high-quality image. The amount of unnecessary radiation a patient receives can also vary in magnitude. A patient who receives a small amount of excess ionizing radiation may experience no immediate signs or symptoms. However, the radiation may have damaged the DNA in the tissues that were exposed, increasing the risk that cancer may develop at that site in the future. A patient who receives a large amount of excess ionizing radiation will experience visible symptoms soon after the procedure. High acute doses of ionizing radiation can cause burns and hair loss, and can increase the risk of developing cataracts if the exposure was directly to the eyes.

Medical imaging procedures where excess radiation exposure may be more likely to cause harm include CT scans, nuclear medicine studies, and fluoroscopy, because they tend to use higher amount of ionizing radiation to begin with.

The goal of this initiative is to reduce unnecessary radiation exposure from CT, nuclear medicine studies, and fluoroscopy, in order to minimize related risks and support the benefits of these exams.

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Are patients who undergo mammography at risk for unnecessary radiation exposure?

The safety and quality of mammography and the amount of radiation associated with mammography procedures are tightly regulated by FDA under the Mammography Quality Standards Act (MQSA). Mammograms, like all imaging studies that use ionizing radiation, can increase the risk of cancer. However, in the case of mammograms the risk is very small and outweighed by the benefits of early detection of breast cancer. This initiative does not pertain to mammography.

For more information about FDA’s oversight of mammography, see: Mammography Quality Standards Act and Program.

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What should providers and patients do to avoid unnecessary radiation exposure?

Providers should review their radiation dosing protocols to ensure the correct dose is planned for each study, and should implement quality control procedures to ensure the dosing protocols are followed every time and the planned amount of radiation is administered.

Providers should also consider whether or not an alternative imaging procedure that does not use ionizing radiation, such as ultrasound or MRI, can be performed in any given case.

Patients should follow their doctors’ recommendations, since medically necessary imaging studies, when administered properly, can provide important health information to guide diagnosis and treatment. However, patients who have questions about a recommended imaging study or about a study they have undergone regarding radiation exposure should speak with their doctors.

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Should members of the public be concerned about radiation exposure from body scanners at airports?

The use of body scanners at airports exposes individuals to a negligible x-ray dose and a miniscule increased risk of cancer. Unlike medical imaging, in which x-rays are used to penetrate the skin to visualize organs and other parts of the body, body scanners use low level x-rays to visualize what is on the surface of the skin. The amount of radiation to which a traveler is exposed from a single body scan is about the equivalent of the amount of radiation he or she would experience during one minute of flight in an airplane at 40,000 feet.

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