The US Food and Drug Administration (FDA) has received a small number of reports of adverse events thought to be associated with CT imaging of some implantable and wearable electronic devices, such as insulin pumps, cardiac implantable electronic devices, and neurostimulators, the agency said today in a safety communication.
The new safety notice updates and replaces the FDA's preliminary public health notice from July 2008 on possible malfunction of electronic devices caused by CT scanning, as reported by Medscape Medical News.
"FDA's current understanding is that when a CT scanner directly irradiates the circuitry of certain implantable or wearable electronic medical devices (i.e. when the device is visible in the resulting CT image), it can cause sufficient electronic interference to affect the function and operation of the medical device," the agency said.
"The probability that this interference can cause clinically significant adverse events is extremely low. Furthermore, the probability of x-ray electronic interference is lower when the radiation dose and the radiation dose rate are reduced," the FDA said. "Interference is completely avoided when the medical device is outside of the primary x-ray beam of the CT scanner."
The FDA emphasized that having an insulin pump, cardiac implantable electronic device, or neurostimulator should not preclude a patient from having an appropriate, medically indicated CT scan.
"The probability of an adverse event being caused by exposing these devices to CT irradiation is extremely low, and it is greatly outweighed by the clinical benefit of a medically indicated CT examination," the agency said.
For physicians ordering a CT scan, the FDA advises that if the CT scan will cover the area over the insulin pump, "discuss with the patient whether the insulin pump can be safely moved, attached at a different location, turned off and for how long, or if alternative diabetes management is required." In addition, this information should be communicated to the imaging facility performing the CT scan to help them plan imaging that will minimize the risk for adverse effects on the function of the insulin pump.
The FDA's safety notice also includes detailed recommendations for radiologists and radiologic technologists on how to handle a patient with an insulin pump, and for physicians managing the patient's diabetes and insulin pump use when a CT scan is planned.
The notice also includes detailed recommendations specific to the patient with cardiac implantable electronic devices and neurostimulators.
The FDA encourages health providers to promptly report adverse events related to the use of CT scanners to MedWatch, the FDA safety information and adverse event reporting program.
CT Scan May Interfere With Electronic Medical Devices. Medscape. Apr 01, 2016.