WASHINGTON (Reuters) - U.S. regulators are probing more cases of patients who were exposed to excess radiation from brain scans performed with equipment from General Electric and Toshiba, government officials said on Monday.
The Food and Drug Administration said some patients received up to eight times the normal amount of radiation. High doses of radiation can cause cataracts and increase the risk of some forms of cancer.
In October, the FDA said it was investigating 206 cases of patients being overexposed to radiation during CT perfusion scans of the brain at Cedars-Sinai Medical Center in Los Angeles during an 18-month period.
The FDA said on Monday it had identified at least 50 more cases at Cedars-Sinai and two other California hospitals. Cases also have been reported in Alabama, FDA officials said.
The excess radiation caused skin redness and hair loss in some patients, the agency said.
The agency has not determined if there were problems with the machines or with how they were used, Dr. Jeffrey Shuren, acting director of the FDA’s device center, told reporters on a conference call.
The FDA issued guidelines on Monday meant to help avoid future problems.
Computed tomography (CT) perfusion scans are used to evaluate blood flow in the brain to diagnose strokes, and also are used to examine the heart.
GE Healthcare spokesman Arvind Gopalratnam said while the company continues to investigate, “we confirm that there were no malfunctions or defects in any of the GE Healthcare equipment involved.”
Toshiba said the FDA had informed the company of one site where potential overradiation occurred with the company’s equipment. “We are cooperating fully with the FDA and working with them to investigate this matter,” said Paul Biggins, head of regulatory affairs for Toshiba America Medical Systems.
Cedars-Sinai spokeswoman Simi Singer said the hospital had documented 260 cases and had disclosed the total in November. The hospital adopted policies in September that were similar to the new FDA guidelines for preventing future cases, she added.
“We continue to work with the FDA and other regulatory agencies to help identify the root causes of this issue,” Singer said.
In the new guidelines, the FDA urged imaging centers to review protocols for CT perfusion scans of the brain and heart and advised technicians to check the display panel before use to make sure the right amount of radiation would be delivered.
“While we do not know yet the full scope of the concern, facilities should take reasonable steps to double-check their approach to CT perfusion studies and take special care with these imaging tests,” the FDA’s Shuren said in a statement.
Ten cases were reported at Glendale Adventist Medical Center in California, FDA spokeswoman Karen Riley said. The hospital issued a statement on the 10 cases in November, saying the patients were exposed to about three to four times the normal radiation dose while undergoing tests with a GE machine and their risk was “minimal.”
The Glendale hospital continues to use the machine but has changed some procedures to avoid future problems, the statement said.
Other cases were identified at California’s Providence Saint Joseph Medical Center with Toshiba equipment but exact figures are unknown, the FDA’s Riley said.
In a statement, the hospital said “to date, we have had no adverse reactions reported due to unnecessary exposure.” The hospital also is “working with the manufacturer to ensure that proper dosages were administered” and is implementing the new FDA recommendations, the statement said.
At least one case was identified at a hospital in Huntsville, Alabama, the FDA’s Riley said.
Reporting by Lisa Richwine and Jackie Frank; editing by Gunna Dickson and Matthew Lewis