The US Food and Drug Administration announced an initiative to reduce unnecessary radiation exposure from three types of medical imaging procedures: computed tomography (CT), nuclear medicine studies, and fluoroscopy. These procedures are the greatest contributors to total radiation exposure within the US population and use much higher radiation doses than other radiographic procedures, such as standard X-rays, dental X-rays, and mammography.

CT, nuclear medicine, and fluoroscopic imaging have led to early diagnosis of disease, improved treatment planning, and image-guided therapies that help save lives every day. The US FDA continues to support a strong dialogue between patients and physicians over the medical necessity and risk associated with these types of imaging studies.

However, like all medical procedures, CT, nuclear medicine, and fluoroscopy pose risks. These types of imaging exams expose patients to ionizing radiation, a type of radiation that can increase a person's lifetime cancer risk. Accidental exposure to very high amounts of radiation also can cause injuries, such as skin burns, hair loss and cataracts. Health care decisions made by patients and their physicians should include discussions of the medical need and associated risks for each procedure.

"The amount of radiation Americans are exposed to from medical imaging has dramatically increased over the past 20 years," said Jeffrey Shuren, director of the US FDA's Center for Devices and Radiological Health. "The goal of FDA's initiative is to support the benefits associated with medical imaging while minimizing the risks."

While there is some disagreement over the extent of the cancer risk associated with exposure to radiation from medical imaging, there is broad agreement that steps can and should be taken to reduce unnecessary radiation exposure.

For example, the radiation dose associated with a CT abdomen scan is the same as the dose from approximately 400 chest X-rays. In comparison, a dental X-ray calls for approximately one-half the radiation dose of a chest X-ray. Both diagnostics serve important, sometimes critical, public health needs.

Through the US FDA's regulatory oversight of medical imaging devices, such as CT scanners, and through collaboration with other federal agencies and health care professional groups, the US FDA is advocating the adoption of two principles of radiation protection: appropriate justification of the radiation procedure and optimization of the radiation dose used during each procedure.

"Working together," said Shuren, "The US FDA and other organizations hope to help patients get the right imaging exam, at the right time, with the right radiation dose."

The three-pronged initiative the US FDA is announcing will promote the safe use of medical imaging devices, support informed clinical decision-making, and increase patient awareness of their own exposure.

The US FDA intends to issue targeted requirements for manufacturers of CT and fluoroscopic devices to incorporate important safeguards into the design of their machines to develop safer technologies and to provide appropriate training to support safe use by practitioners. The agency intends to hold a public meeting on March 30-31, 2010, to solicit input on what requirements to establish.

Examples could include a requirement that these devices display, record, and report equipment settings and radiation dose, an alert for users when the dose exceeds a diagnostic reference level (the optimal dose for most patients), training for users, and a requirement that devices be able to capture and transmit radiation dose information to a patient's electronic medical record and to national dose registries.

In addition, the US FDA and the Centers for Medicare and Medicaid Services are collaborating to incorporate key quality assurance practices into the mandatory accreditation and conditions of participation survey processes for imaging facilities and hospitals. These quality assurance practices will improve the quality of oversight and promote the safe use of advanced imaging technologies in those facilities.

The US FDA recommends that health care professional organizations continue to develop, in collaboration with the agency, diagnostic radiation reference levels for medical imaging procedures, and increase efforts to develop one or more national registries for radiation doses.

A dose registry would pool data from many imaging facilities nationwide, capturing dose information from a variety of imaging studies. This registry will help define diagnostic reference levels where they do not yet exist, validate levels that do exist, and provide benchmarks for health care facilities to use in individual imaging studies.

In a bid to empower patients and increase awareness, the US FDA is collaborating with other organizations to develop and disseminate a patient medical imaging history card. This tool, which will be available on the US FDA's Web site, will allow patients to track their own medical imaging history and share it with their physicians, especially when it may not be included in their medical records.