The Food and Drug Administration said Tuesday that overdoses of radiation to more than 400 patients undergoing CT scans of their heads were due to operator error and called on manufacturers to make changes to prevent such mistakes in the future.
In a statement on its website and in a letter to manufacturers, the agency recommended that the companies compile all dosing information in an easily accessible form for operators and that they install a pop-up device to warn operators before they administer a dangerous overdose.
The overdoses were first observed at Cedars-Sinai Medical Center in Los Angeles, where at least 260 patients have received as much as eight times the normal radiation dose from a General Electric scanner. The hospital cited confusion over computerized instructions that control the radiation dose and scan quality.
The FDA said it was aware of at least 385 patients from six hospitals who had been exposed to excess radiation, but independent counts showed more than 400 cases.
A normal CT scan is estimated to carry about 400 times as much radiation exposure as a chest X-ray. Some patients have thus received the equivalent of 3,200 chest X-rays, a dosage that carries a significant cancer risk.
Some of the patients have reported hair loss and other problems.