Doctors have expressed outrage and concern for the unsuspecting patients who received eight times the normal dose of radiation during a specific type of brain scan at Cedars-Sinai Medical Center in Los Angeles.
The overdose was discovered when a patient reported lost patches of hair following a CT scan.
The error, which Cedars-Sinai attributed to a "misunderstanding" about an incorrectly programmed CT machine, in a statement released Oct. 12, remained unchecked for 18 months, involved 206 people, and exacerbated existing concerns that patients nationwide are being exposed to excess radiation during medical testing.
"To me, even as a professional, this is a fairly shocking story. These patients received 8-10 times the normal dose for a head CT and probably reached their allowable radiation exposure for the year at a single test," said Dr. James Slater, associate professor of cardiology at the NYU Langone Medical Center. "The fact this error occurred and went undetected for 18 months at a well regarded medical [institution] is rather unbelievable."
Diagnostic imaging tests have increased Americans' average radiation exposure seven times since 1980, according to the National Council on Radiation Protection and Measurements, and increased exposure leads to increased cancer risk.
While occupational radiation exposure is regulated by the government, there is no federal oversight when radiation is used for medical purposes.
"There is no government limit on what you can give a patient when it's a diagnostic test," said Dr. Gary Freedman, a radiation oncologist at Fox Chase Cancer Center in Philadelphia. "It's assumed that medically, you do what you need to do and worry about the complications later."
But the radiation doses that the Cedars-Sinai patients received were significantly higher than intended. In some cases, these patients, who were undergoing CT brain perfusion scans, often used to monitor stroke patients, received twice as much radiation as the average cancer patient would receive in one treatment.
That much radiation in a single dose can be enough to cause temporary hair loss, and is certainly high enough to cause skin redness and irritation, Freedman said. Cedars-Sinai reported that 40 percent of the affected patients experienced redness and hair loss.
Still, doctors said the chance that a one-shot exposure to excess radiation would increase the risk of developing cancer or have other significant long-term health effects in these patients -- whose average age was 70 -- was small.
"Fortunately in this case, there appears to be no evidence that patients have suffered any life-threatening or irreversible injury [including] neurologic injury," said Dr. Leonard Berlin, professor of radiology at Rush University Medical College. "Reactions to the radiation exposure are regrettable and uncomfortable, but fortunately, will spontaneously disappear without any residual effect."
The most pressing issue, after seeing whether patients were permanently harmed, is that the error went uncorrected for over a year.
"The risk of further tumors is really small," Freedman said. "But this was an error and it's not OK that [patients] got eight times what they should have...
"Probably in this case it made no clinical difference," said Freedman, "but this shouldn't reassure us that next time there wouldn't be a serious overdosage."
Dr. Brahmajee Nallamothu, cardiologist and researcher at the University of Michigan/VA Patient Safety Enhancement Program, said the news of patients getting excess radiation at Cedars-Sinai prompted hospital staff to recheck their CT brain perfusion scan protocol to make sure their machines were working properly.
The FDA also issued an alert last Thursday, urging hospitals nationwide to review their safety protocols for CT scans.
But financial obstacles could prevent proper quality control at many health care facilities.
"I am concerned by the economic pressures that may lead health care systems to lay off physicists and engineers that do not provide clinical revenue, yet they are our radiation safety experts that work hand in hand with the diagnostic radiologists," said Dr. Kimberly Applegate, vice chair of quality and safety in the department of radiology at Emory University School of Medicine. "Ionizing radiation cannot be detected by our natural senses, so we must ensure appropriate dose tracking and quality control of our equipment."
And diagnostic machines that use radiation, including X-ray and CT machines, have spread to private doctors' offices, outpatient facilities and free-standing medical centers, raising concerns about appropriate testing and calibrating, said Dr. Len Lichtenfeld, deputy chief medical officer of the American Cancer Society.
"The volume of CT scans we're doing in the country is considerable," said Lichtenfeld. But he added that the need to reduce radiation is offset by the clinical information necessary to help a patient.
Some doctors suggested that tracking a patient's cumulative radiation dose in their medical record, similar to how cholesterol or hemoglobin is recorded, may help prevent unnecessary radiation exposure.
"It is the wild west out there," said Dr. Richard Semelka, vice chair of quality and safety in the department of radiology at UNC Hospitals. "No one has solved the issue of keeping track of the global exposure of individuals to medical radiation."
Accreditation programs from the American College of Radiology (ACR) for facilities with CT machines could help prevent future errors such as this through consistent guidelines for protocol oversight and standards.
However, only 4,000 facilities nationwide are accredited, according to Shawn Farley, director of public affairs for the ACR, and Cedars-Sinai is not one of these. Farley pointed out that, while a new Medicare rule will force facilities to become accredited, this law does not go into effect until Jan. 1, 2012.
Cedars-Sinai said in a statement that it has instituted "double checks" when protocols are changed, and that an investigation into the incident is underway.