FDA Wants New Safety Standards for Some X-Rays

Feb. 10, 2010— -- WASHINGTON -- The U.S. Food and Drug Administration (FDA) says it wants to issue new safety requirements for manufactures of computed tomography (CT) and fluoroscopic devices to reduce unnecessary radiation from medical imaging.

The FDA's plan focuses on three procedures with high radiation doses: CT, nuclear medicine studies, and fluoroscopy. These are the greatest contributors to total radiation exposure within the United States population, the FDA said. That's because they require much higher radiation doses than other radiographic procedures, such as standard X-rays, dental X-rays, and mammography.

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

While the three procedures have led to early diagnosis of disease, they expose patients to ionizing radiation that may increase lifetime cancer risk -- although there is debate within the medical community about the extent of the danger.

Radiologist Dr. Joseph Schoepf, director of Cardiovascular Imaging at the Medical University of South Carolina, lauded the FDA's initiative and said it would restore the public's trust in imaging.

"It is important to note, however, that an increase in cancer mortality [from radiation] has not been observed," added. "On the contrary, cancer mortality has dramatically decreased over the past decades, in step with increased utilization of medical imaging."

The Archives of Internal Medicine recently published results from two studies indicating that CT scans deliver much higher doses of radiation than previously thought. The FDA has noted that a patient would have to get 400 standard chest X-rays to be exposed to the same level of radiation as just one CT abdomen scan.

In an accompanying editorial, the journal's editor, Rita Redberg, wrote that the studies "make us question if we have gotten carried away in our enthusiasm" for CT.

It's becoming clear, she said, that the large doses of radiation from CT scans will lead to additional cancers, which must be taken into account when physicians consider CT for their patients.

By working with health care providers and other federal agencies, the FDA says it hopes to promote safer use of medical imaging and increase patient awareness of their radiation exposure. Part of that involves pushing providers to justify their radiation procedures and optimize the radiation dose in each one.

Schoepf, who serves on several American College of Radiology committees that discuss the proper used of various imaging procedures, approved of the FDA's goal but cautioned against restrictions that would hinder clinicians.

"There is indeed a need for enhanced transparency, better patient education, more dialogue between patients and their health care providers, and increased involvement of the patient in the decision process leading up to an imaging study," Schoepf said.

"What is often forgotten in this discussion is that serious injury or death, resulting from missing a potentially life-threatening diagnosis if no imaging is performed is a much greater, more imminent, and very real risk," he said.

In its statement, the FDA said wants to boost efforts to develop at least one national registry of radiation doses that will capture information from a variety of imaging studies that can be used to establish benchmarks for health care facilities to use with patients.

The ACR launched a similar registry about a year ago, according to spokesman Shawn Farley. The database is intended as a guide so a radiologist can quickly see how levels of radiation delivered in other practices and hospitals compare to what he or she is delivering.

"Now that the FDA has come out in favor of doing that, we're hoping that will put a little more weight behind the process and make more facilities want to take part in this," Farley told MedPage Today.

The FDA will hold a public meeting March 30 and 31 to hear comments on what types of safety requirements to establish for manufacturers of CT and fluoroscopic devices. Requirements might include:

That the radiation device display, record, and report equipment settings and radiation dose

Alerting users when the dose exceeds the optimal dose for most patients

Increased training for users

Ability to capture and transmit radiation dose information to a patient's electronic medical record in addition to national dose registries

This article was developed in collaboration with ABC News.