Only later would Mr. Reyes learn what had caused him so much physical and emotional grief: he had received a radiation overdose during a test for a stroke at a hospital in Glendale, Calif.
Other patients getting the procedure, called a CT brain perfusion scan, were being overdosed, too — 37 of them just up the freeway at Providence Saint Joseph Medical Center in Burbank, 269 more at the renowned Cedars-Sinai Medical Center in Los Angeles and dozens more at a hospital in Huntsville, Ala.
The overdoses, which began to emerge late last summer, set off an investigation by the FDA into why patients tested with this complex yet lightly regulated technology were bombarded with excessive radiation. After 10 months, the agency has yet to provide a final report on what it found.
But an examination by The New York Times has found that radiation overdoses were larger and more widespread than previously known, that patients have reported symptoms considerably more serious than losing their hair, and that experts say they may face long-term risks of cancer and brain damage.
The review also offers insight into the way many of the overdoses occurred. While in some cases technicians did not know how to properly administer the test, interviews with hospital officials and a review of public records raise new questions about the role of manufacturers, including how well they design their software and equipment and train those who use them.
The Times found the biggest overdoses at Huntsville Hospital — up to 13 times the amount of radiation generally used in the test.
Officials there said they intentionally used high levels of radiation to get clearer images, according to an inquiry by the company that supplied the scanners, GE Healthcare.
Experts say that is unjustified and potentially dangerous.
“It is absolutely shocking and mind-boggling that this facility would say the doses are acceptable,” said Dr. Rebecca Smith-Bindman, a radiology professor who has testified before Congress about the need for more controls over CT scans. Yet because the hospital said no mistakes were made, regulatory agencies did not investigate.
The F.D.A. was unaware of the magnitude of those overdoses until The Times brought them to the agency’s attention. Now, the agency is considering extending its investigation, according to Dr. Alberto Gutierrez, an F.D.A. official who oversees diagnostic devices.
Patients who received overdoses in Huntsville say that in addition to hair loss, they experienced headaches, memory loss and confusion. But at such high doses, experts say, patients are also at higher risk of brain damage and cancer.
A spokesman for Huntsville Hospital, which now acknowledges that some patients received “elevated” radiation, said officials there would not comment.
Growing Number of Cases
So far, the number of patients nationwide who got higher-than-expected radiation doses exceeds 400 at eight hospitals, six in California alone, according to figures supplied by hospitals, regulators and lawyers representing overdosed patients. A health official in California who played a leading role in uncovering the cases predicts that many more will be found as states intensify their search.
“I cannot believe that this is not occurring in the rest of the country,” said Kathleen Kaufman, head of radiation management for the Los Angeles County Department of Public Health. “That’s why we are so keen on the rest of the states to go look at this.”
The Food and Drug Administration acknowledges, too, that the number does not capture all the overdoses.
The cases come at a time when Americans are receiving more medical radiation than ever before, a result of rapid technological advancements that improve diagnosis but can also do harm when safeguards and oversight fail to keep pace.
Even when done properly, CT brain perfusion scans deliver a large dose of radiation — the equivalent of about 200 X-rays of the skull. But there are no hard standards for how much radiation is too much. The overdoses highlight how little some in the medical profession understand about the operation of these scanning devices and the nature of radiation injuries, as well as the loose requirements for reporting accidents when they are detected.
For a year or more, doctors and hospitals failed to detect the overdoses even though patients continued to report distinctive patterns of hair loss that matched where they had been radiated. After the Food and Drug Administration issued a nationwide alert asking hospitals to check their radiation output on these tests, a few hospitals continued to overdose patients for weeks and in some cases months afterward, according to records and interviews.