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  1. Science and Research (Medical Devices)

Electromagnetic Dosimetry

Electromagnetic Dosimetry

Contact

Howard Bassen

Summary

This group supports the agency’s regulatory research roles by advancing our knowledge on the complex interactions between electromagnetic (EM) fields and the human body or other objects such as models of cardiac pacemakers implanted in the body. We coordinate research closely with the EM modeling program. The research combines computational models and experimental techniques applied to several areas of clinical significance, including the: 1) analysis of radiofrequency (RF)-induced heating in patients with implanted medical devices undergoing Magnetic Resonance Imaging (MRI); and 2) assessment of electromagnetic energy deposition by diathermy and airport millimeter wave sources such as cellular phones and radio and television broadcast towers.

This program has a direct impact on the regulatory mission of the agency, as the tools developed by our research are used by industry in pre-market evaluation of safety and effectiveness of their medical devices. The research is funded by external support from the transportation security administration (TSA).

AIT scanner and a PMED being placed in it for testing

AIT scanner and a PMED being placed in it for testing.


Fields in MRI Coil

Electric field plots in an MRI coil comparing measured with computed results.


Fields induced in body

Computed electric field plots in a human tissue model showing penetration depth.

The electromagnetic compatibility (EMC) and wireless lab has a long history of working with other federal agencies on issues involving medical device EMC. Presently, the EMC-wireless lab is engaged in an agreement with the Transportation Security Administration (TSA) to evaluate potential safety issues for the passengers screened and security personnel with the next generation of advanced imaging technology (AIT) millimeter waves (mmW) whole body security scanner systems. These AIT systems use small levels of radio waves in the mmW spectrum to help create the security screening image. TSA and FDA share common interest in assessing the potential risks for passengers with Personal Medical Electronic Devices (PMEDs) such as implanted cardiac pacemakers and cardioverter-defibrillators, implanted and body worn neurostimulators, and body worn insulin pumps. Measurements and analysis by the EMC-wireless lab researchers assessed the human exposure risks of passengers passing through an AIT and nearby security personnel finding these exposure levels to be many thousand times below the limits set by International radiation safety standards organizations. The research also included tests of several sample PMEDs for exposure to the AIT system as well as a novel system developed in the lab that simulates the AIT exposure in ways that can be more controlled. None of the PMEDs showed signs of effects during or after the AIT exposures

Current external funding sources

Transportation Security Administration (TSA)

Personnel

FDA Staff:
Howard Bassen, MSc
Leonardo Angelone, Ph.D.
Maria Iacono, Ph.D.
Wolfgang Kainz, Ph.D.
Sunder Rajan, Ph.D.

Research Fellows:
Elena Lucano
Gonzalo Mendoza
Amir Razjouyan
Peter Serano

Resource facilities

Hardware

  • Magnetic resonance imaging (MRI) Gradient coil simulator with amplifiers (MRCOMP, Germany)
  • Magnetic resonance imaging (MRI) coils (64MHz and 128MHz) (MITS, Zurich, Switzerland)
  • DASY5 Robotic Electric and magnetic field measurements system (Zurich, Switzerland)
  • 10 meter fully anechoic chamber
  • Tissue implantable electric and magnetic field probes.

Software

  • Sim4Life Electromagnetic and thermal solvers (SPEAG)
  • SemcadX Electromagnetic and thermal solvers
  • XFDTD (Remcom)

Relevant standards

IEEE Std C95.3.1™-2010, IEEE Recommended Practice for Measurements and Computations of Electric, Magnetic, and Electromagnetic Fields with Respect to Human Exposure to Such Fields, 0 Hz to 100 kHz

Sponsor IEEE International Committee on Electromagnetic Safety

IEEE Std 1528™-2003, IEEE Recommended Practice for Determining the Peak Spatial-Average Specific Absorption Rate (SAR) in the Human Head from Wireless Communications Devices: Measurement Techniques Sponsor Standards Coordinating Committee 34 (Product Performance Standards Relative to the Safe Use of Electromagnetic Energy)

Selected peer-review publications