CT Brain Perfusion Scan Radiation Overdose FDA Investigation

According to an FDA alert, at least 206 patients in an 18-month period received extremely high radiation doses when they were undergoing perfusion CT imaging. Specifically, the FDA says that the patients were expected to receive a dose of 0.5 Gy (maximum) to their head but instead received 3-4 Gy.

An article in The New York Times (October 15, 2009) notes that Cedars-Sinai Hospital disclosed that it had accidentally exposed patients to high doses of radiation. Meanwhile, in an incident unrelated to the FDA CT scan alert at Cedars-Sinai, at Mad River Community Hospital in Arcata, California, an x-ray technician has lost her state license for reportedly putting a 2½ year old through more than an hour of CT scans, according to the same article in The New York Times.

The FDA alert notes that some patients experienced hair loss and erythema (redness of the skin). However, also of concern is that overexposure to radiation that is not at doses high enough to produce obvious signs of radiation injury may put patients at risk for long-term radiation effects. Furthermore, there is a concern that the problem may be more widespread than just one facility.

"While this event involved a single kind of diagnostic test at one facility, the magnitude of these overdoses and their impact on the affected patients were significant," the FDA alert states. "This situation may reflect more widespread problems with CT quality assurance programs and may not be isolated to this particular facility or this imaging procedure (CT brain perfusion)."

CT Scanner Set at Incorrect Levels

According to an article in the Los Angeles Times, the CT scanner involved in the Cedars-Sinai incidents had been set at incorrect levels for 18 months, after the hospital made an error while reconfiguring the scanner.

The FDA has stated that all patients who were exposed to excess radiation have been notified. According to The New York Times, Cedars-Sinai said that its own flawed procedures were responsible for the overdoses, but also said that the manufacturers could install more safeguards to prevent such situations.

Perfusion CT imaging is conducted in urgent situations to identify any potential problems with blood flow in the brain. One situation in which it is used is to diagnose a stroke.

In a written statement, (quoted in the Los Angeles Times) Thomas M. Priselac, chief executive at Cedars-Sinai said, "We take very seriously our responsibility for operating medical equipment in the safest possible manner, and deeply regret the circumstances that led to patients undergoing CT brain perfusion studies receiving a higher than appropriate level of radiation."