It was three months ago when Cedars-Sinai Medical Center in Los Angeles announced that over an 18-month period, 260 patients had been exposed to unusually high—eight times higher than normal—radiation doses from CT brain scans. Then a similar situation occurred at Glendale Adventist Medical Center, also in Los Angeles county, although there were only 10 patients affected. Their doses were three or four times normal levels. By December, a third county hospital had reported radiation overdoses, this time Providence St. Joseph Medical Center in Burbank. In addition, a woman who received a CT brain scan at Huntsville Hospital in Alabama received an even higher dosage than the Cedars-Sinai patients. Overall, more than 300 people received elevated doses of radiation.
These incidences were especially mysterious because the equipment could not be traced back to a single manufacturer. In several cases, General Electric manufactured the scanners. A Toshiba machine was involved in the Burbank incident.
“Given the fact that we are dealing with two manufacturers and multiple institutions, we wouldn’t be surprised” to find problems elsewhere, then-acting CDRH director Jeffrey Shuren told the Los Angeles Times late last year.
The center is urging CT technologists to “go back to basics” to ensure that patients receiving CT perfusion scans are not exposed to excess radiation. Shuren told a media briefing in December that FDA is making recommendations for facilities and technologists to follow for all CT perfusion scans while the agency continues its investigation to determine whether problems lie with the equipment, human error, or a combination of the two. He said that over time, facilities may rely on algorithms to calculate the appropriate dosage and that FDA recommends that technologists verify before all scans that the dosage is appropriate for the patient. The agency’s recommendations are as follows:
? Facilities assess whether patients who have undergone CT perfusion scans received excess radiation.
? Facilities review radiation dosing protocols for all CT perfusion studies.
? Facilities implement quality control procedures.
? Radiologic technologists check the CT scanner display panel before performing a study.
? If more than one study is performed on a patient during one imaging session, practitioners should adjust the radiation dose so that it is appropriate for each study.
When reporters said that the recommendations seem to be things that should be done routinely, CDRH Division of Mammography Quality and Radiation Programs associate director Charles Finder said that FDA’s intention was to remind facilities and staff of routine good practices.
Shuren said that it is important for patients who have been exposed to excess radiation to be seen by their doctor.
