CT radiation causes implanted devices to malfunction

The FDA cautioned healthcare CT users July 16 that ionized radiation generated during CT exams may cause some implanted and external electronic medical devices to malfunction. Though rare, the incidence of radiation-induced pacemaker and implantable device malfunction has risen with increased multislice CT use, said Dr. Daniel G. Schultz, director of the FDA Center for Devices and Radiological Health. Patients implanted with pacemakers, defibrillators, neurostimulators, and implanted or externally worn drug infusion pumps are at risk. The FDA recommended CT scout views to determine the presence of an implanted or externally worn electronic medical device. The location of the device relative to the programmed scan range should be noted.

The agency recommended the following precautions for patients with the devices:

• Determine the device type.
• Attempt to move external devices out of the scan range, if possible.
• Ask patients turn off neurostimulators during CT scanning.
• Minimize radiation exposure by using the lowest possible tube current.
• Make sure the x-ray beam does not dwell over the device for more than a few seconds.

Attending staff should be prepared for emergency measures when CT perfusion or other procedures require more than a few seconds of scanning over the device, Schultz said.

For more information from the Diagnostic Imaging archives:

Pacemaker may skip a beat during routine scan