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.
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.