Cedars-Sinai CEO Tom Priselac Thursday listed four recommendations to improve the function of 64-slice CT scanners after 206 patients there received CT brain perfusion studies with eight times normal radiation.
In one of those recommendations, he suggested the machine's function may be improved with adjustments to the machine's auto function setting.
"Based on our understanding of the machine's auto functions, it should not have delivered an excessive dose. The auto function on CT scanners is used to provide the best quality of image using the lowest necessary dose," Priselac wrote in a two-page statement.
"We present this information not to shift responsibility, but to maximize patient safety by involving manufacturers in the process of continually improving processes and equipment," Priselac wrote.
The statement read: "The embedded default setting for image noise in the auto function in the 64-slice scanner, which was supplied by the manufacturer, did not match the manufacturer's recommended settings. The default applied by the machine in a CT brain perfusion scan is different from that applied during regular CT brain scan. As a result of the default's lower noise setting, the amount of radiation delivered was higher than expected."
According to the U.S. Food and Drug Administration, which, along with the California Department of Public Health is investigating the incident, the machine in use at Cedars Sinai is manufactured by GE Healthcare.
GE spokesman Arvind Gopalratnam said last week that "there were no malfunctions or defects in any of the GE Healthcare equipment involved in the incident" and emphasized that "patients and families should continue to have confidence in their doctor's recommendation for a CT scan."
Asked last night for additional comment after the release of Priselac's statement, Gopalratnam said, "Due to the pending investigation, we cannot comment right now. As the investigation progresses, we'll be able to share more in the future."
Priselac said the hospital wants to convey information "that we believe may be helpful to the FDA, scanner manufacturers and other hospitals in order to prevent this type of situation from occurring elsewhere."
In addition to adjusting the default settings, Priselac recommends that the FDA consider reviewing and revising the machinery's dose display, alerts, and forced functions and that there be additional password protections.
- Dose Display: "The dose display on the screen of the scanner could be enhanced to facilitate ease of use by the technologists. This is especially true for time-sensitive scans such as CT brain perfusion, which is often performed urgently in the middle of a patient's stroke to determine the most appropriate treatment to preserve blood flow to the brain."
- Alerts and forced functions: "Currently there is no forced function on the equipment requiring technologists to proceed with the scan only after confirming they have reviewed the appropriate dose. There could be more assertive audible or visual alerts on the scanners to indicate prior to scanning that the anticipated dose may be high."
- Additional password protecting: "Certain settings on the equipment, particularly those with a high potential of resulting in an inappropriate level of radiation, should be password protected and only accessible for change by the manufacturer."
The problem with the 64-slice CT was noticed in August when a patient, who had previously received a scan, complained of patchy hair loss. When hospital officials looked through their records, they discovered 206 patients had received the scans over the previous 18 months. Of those, 40% who have been contacted also had patchy hair loss or reddening of skin believed to be linked to excessive radiation.
In his statement, Priselac 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."
He said the dosage was "similar to the amount they might receive when undergoing a complex interventional procedure. We will continue to work with all affected patients to address any questions or concerns they may have."
Barry Pressman, MD, who chairs the hospital's Department of Imaging, said that the radiation "was higher than expected, but similar to an amount they might receive when undergoing a procedure such as angioplasty. As a physician speaking with patients, the goal is to address any side-effects that may occur, without unnecessarily alarming them, he said.
"In addition, our physicians addressed any concerns or questions the patients had, including questions from some patients about the radiation level," Pressman said. "We continue to respond to patients' questions and concerns. I sincerely regret if any patient feels they did not receive the information they needed."
Priselac, who also is this year's president of the American Hospital Association, said his hospital has made four changes as a result of its investigation.
They include "changes to assure proper validation of radiation levels at the time protocols are changed, improved access control over protocol changes and additional redundancy in the methods used to confirm radiation dose levels," according to Priselac.
The four changes are:
- Protocol changes can only be initiated by Department of Imaging Section Chiefs, and must be clearly documented.
- All changes will be reviewed by the radiation physicist to confirm they will not result in higher than appropriate doses.
- After review and approval by the radiation physicist, authority to change standard protocol settings can only be updated in the scanners by the supervisor, and their ability to make setting changes is password protected.
- In-service training for technologists on any changes to standard protocols and dose alerts will be expanded, and will be clearly documented.
Cedars-Sinai officials did not respond to reports published in yesterday's Los Angeles Times that four patients may have been exposed to excessive doses of radiation.
Hospital officials also have not responded to questions about how they are following and monitoring the patients to determine whether they develop any conditions or diseases that may be linked to the overdoses.
Meanwhile, a spokeswoman for the FDA said Friday that "the FDA has not made a determination on the cause of this issue."