Nationwide cumulative-dose indices, warning flags in electronic medical records (EMRs), and electronic imaging-history smart cards: All these are being called for to protect patients from excessive radiation exposure. The real advances on this hot-button issue for radiology, however, are taking place at the health-facility level, one patient at a time.
In a watershed moment in October 2009, a luminary medical center in Los Angeles, California, announced that it had completed CT brain-perfusion scans of 206 patients over a period of 18 months, during which patients mistakenly had received eight times the called-for radiation dose per scan. The incident spawned lawsuits and a flood of media attention. The news stories were kept alive when more incidents of radiation overexposure were reported at other hospitals in California and in Alabama.
Two months later, one of a pair of radiation-dose studies¹,² that appeared in the Archives of Internal Medicine estimated that as many as 29,000 patients nationwide could develop cancer from normal levels of CT-exam radiation, and that 14,500 of them could die.
Enter the FDA, which began an investigation of the overexposure events. That investigation continues, but the FDA hasn’t waited for its results to act. In February 2010, the agency announced a three-pronged initiative to control radiation exposure in patients undergoing CT, fluoroscopy, and nuclear-medicine exams. The FDA’s three attack points are promoting safe use of imaging devices, enhancing informed clinical decision making on imaging exams, and making patients aware of the risks that they face from radiation exposure during imaging.
In February, the House of Representatives held hearings during which members of Congress expressed shock at the lack of regulation of radiation exposure during clinical imaging. The National Institutes of Health (NIH) also mandated that all vendors selling imaging systems to NIH include dose-tracking technology on those machines.
At the end of March, the focus swung back to the FDA for a two-day series of meetings and seminars at which imaging-industry trade groups, manufacturers, and professional societies assessed steps that could be taken to control radiation exposure during imaging.
Calls for Accreditation
One of those testifying at the March FDA panels was E. Stephen Amis Jr, MD, FACR. Amis is professor and chair of the radiology department at the Albert Einstein College of Medicine and its teaching hospital, Montefiore Medical Center, in the Bronx, New York. He is also the former chair of an ACR® Blue Ribbon Panel on Radiation Dose in Medicine. He is the current cochair of the RSNA–ACR Joint Task Force on Adult Radiation Protection.
Amis says that the risk from radiation exposure due to medical imaging is modest, but real. Since patients in the United States now undergo about 72 million CT scans per year, researchers are probably correct in estimating that 28,000 new cancers will result, he says. In 1980, he adds, only 3 million CT scans were done. CT is the major culprit in delivering high levels of radiation to patients, with some CT tests, according to news reports,³ packing a radiation punch equal to that of 400 radiography exams. Amis says, however, that some nuclear-medicine procedures and fluoroscopic exams also deliver high doses of radiation.
Amis advocates moving quickly, on the national level, to impose controls on patient exposure. The ACR is one of two major accrediting bodies providing accreditation for CT systems. “We’d like to see every CT in the United States accredited,” Amis says. “Right now, only about 40% are accredited.” He says that accreditation forces imaging providers to submit live-patient and phantom exam data to the accrediting body to confirm that systems are functioning properly.
Amis told those at the March FDA meetings that establishing a national dose-index registry, using a standardized method for calculating radiation dose for every exam, should be imposed on equipment manufacturers industry wide. The exposure data should be included in the EMR, he adds, but that should only happen with new machines, as they are developed. He says, “There’s not much enthusiasm for going backward.”
Amis notes that it’s important to develop uniform national licensing standards for radiologic technologists. “The thing that caught everybody’s attention at the FDA meetings was that there are no uniform technologist-licensure standards. A third of the states