About FDA

Description: CDRH/OSEL’s Division of Physics (DP) provides test and analytic data about malfunctions due to a lack of EMC of medical devices. Malfunctions can be caused by a wide range of electromagnetic field emitting devices, from cellular phones to airport security. By proactively identifying the susceptibility of devices to new and emerging sources of radiofrequency interference, OSEL enables manufacturers and users to prevent and avoid malfunctions.

Accomplishment: The project was successfully completed as follows:

• Radiofrequency Identification (RFID) Systems Emitters: Six active implantable neurostimulators with lead systems were tested for susceptibility to electromagnetic fields generated by 22 RFID emitters. Test results showed the output of one of the implantable neurostimulators was inhibited by 2 different 134 kHz RFID emitters at separation distances of 10 cm or less. These events were deemed not clinically significant due to the transient nature and short separation distance of the effects along with the intended use of the particular neurostimulator. CDRH published two peer review journal articles in this area: (1) Electromagnetic compatibility of implantable neurostimulators to RFID emitters, and (2) Analysis of induced electrical currents from magnetic field coupling inside implantable neurostimulator leads .

• Automatic External Defibrillators (AEDs) Related to RFID Exposures: AEDs were exposed to 19 different RFID readers and one RFID active tag. The RFID systems used covered 5 different frequency bands: 125-134 KHz (low frequency [LF]); 13.56 MHz (high frequency [HF]); 433 MHz; 915 MHz (ultra high frequency [UHF]) and 2.4 GHz. We tested 4 AEDs and developed an internal report of findings.

• Hearing Aid/Cell Phone Compatibility: With our collaborators from Gallaudet University we have completed our GTEM measurements of interference susceptibility for representative hearing aids. A report has been prepared for the IEEE C63.19 standards committee proposing a new method of GTEM measurement that increases accuracy and repeatability while decreasing total test time.

• Body-worn and Implanted Medical Devices Related to Airport Body Scanners: A system was developed to simulate the emissions from the advanced imaging technology (AIT) millimeter wave (mmW) security system. Novel test methods were developed to simulate the human body and configuration of the medical devices being examined, and were used to perform testing on a range of personal electronic medical devices (PMEDs), including implantable cardiac pacemakers and defibrillators, implantable neurostimulators, and body worn insulin pumps. No effects on the function of any of these devices were observed. Findings and assessments were provided to DHS/TSA in a detailed report.