Excess radiation exposure during CT perfusion imaging: FDA issues interim recommendations

As part of an ongoing investigation into cases of excess radiation during CT perfusion imaging of the brain, the U.S. Food and Drug Administration today provided imaging facilities and practitioners with interim recommendations to help prevent additional problems.

The FDA issued an initial safety notification in October after learning of 206 patients who had been exposed to excess radiation at Cedars-Sinai Medical Center in Los Angeles over an 18-month period.

Since then, the FDA, working with state and local health authorities, has identified at least 50 additional patients who were exposed to excess radiation of up to eight times the expected level during their CT perfusion scans. These cases so far involve more than one manufacturer of CT scanners. The FDA has also received reports of possible excess radiation from other states. Some of these patients reported hair loss or skin redness following their scans. High doses of radiation can cause cataracts and increase the risk of some forms of cancer.

On the basis of its investigation to date, the FDA is providing interim recommendations for imaging facilities, radiologists, and radiologic technologists to help prevent additional cases of excess exposure. These recommendations apply to all CT perfusion images, including brain and heart, because they use similar procedures and protocols.

These recommendations include:

1. Facilities assess whether patients who underwent CT perfusion scans received excess radiation.
2. Facilities review their radiation dosing protocols for all CT perfusion studies to ensure that the correct dosing is planned for each study.
3. Facilities implement quality control procedures to ensure that dosing protocols are followed every time and the planned amount of radiation is administered.
4. Radiologic technologists check the CT scanner display panel before performing a study to make sure the amount of radiation to be delivered is at the appropriate level for the individual patient.
5. If more than one study is performed on a patient during one imaging session, practitioners should adjust the dose of radiation so it is appropriate for each study.

The FDA continues to work with manufacturers, professional organizations, and state and local public health authorities to investigate the scope and causes of these excess exposures.

The agency is also advising manufacturers to review their training for users, reassess information provided to health care facilities, and put into place new surveillance systems to identify problems quickly.

"The FDA is making progress in the investigation of this problem," said Jeffrey Shuren, M.D., acting director of the FDA's Center for Devices and Radiological Health. "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."

CT or CAT scanning refers to computed tomography, a form of medical imaging that uses X-rays to produce 3-dimensional images to help physicians diagnose and treat medical conditions. CT perfusion scans evaluate blood flow in various organs such as the brain and the heart.

Patients should follow their doctor's recommendations for receiving CT scans. Medically necessary CT scans, administered properly, can provide important health information to guide diagnosis and treatment. Patients who have undergone a CT perfusion scan and have questions regarding radiation exposure should speak with their doctor.

The FDA requires hospitals and other user facilities to report deaths and serious injuries associated with the use of medical devices. If an adverse event is identified, health care professionals should follow the reporting procedures at their facility. Report these directly to the device manufacturer or to MedWatch, the FDA's voluntary reporting program. This can be done on-line by filing a voluntary report, by phone at 1-800-FDA-1088, or by obtaining the fillable form online, print it and fax to 1-800-FDA-0178 or mail to MedWatch, 5600 Fishers Lane, Rockville, MD 20852-9787.

CT Brain Perfusion Scans Safety Investigation: Initial Notification
http://www.fda.gov/Safety/MedWatch/SafetyInformation/SafetyAlertsforHumanMedicalProducts/ucm186105.htm