Electromagnetic Interference With Medical Implants

Electromagnetic Interference with Medical ImplantsGary R. Olhoeft, PhD Professor of Geophysics Colorado School of Mines

8 November 2009

What does a Professor of Geophysics know about electromagnetic interference with medical implants?

Professor of Geophysics

I make very sensitive electrical, magnetic and electromagnetic measurements to study the roots of earthquakes and volcanoes,

Professor of Geophysicsfind oil, mineral and water resources,

Professor of Geophysics

assess environmental contamination,

Professor of Geophysics

characterize infrastructure,

Professor of Geophysics...and study, the sun, moon and planets.

What are EMI and RFI? Interference is any unwanted effect such as music playing too loud for you to hear a phone conversation (signal to music listener but noise to phone user) EMI: Electromagnetic interference is electric or magnetic fields producing an unwanted effect (typically at low frequency by induction) RFI: Radiofrequency interference is electromagnetic fields producing an unwanted effect (typically at high frequency by radiation)

EMI/RFI Interfere with Geophysics Cell phones, radio, TV and power lines are all sources of signal to users and of noise and interference to geophysics Natural fields from the earth and sun are both sources of noise and interference, and also signal What is a desirable signal and what is an unwanted noise depends on the problem and perspective (like the music and phone)

I have a medical implant: Deep Brain Stimulator

Medical Implants Cardiac pacemakers/defibrillators Neurostimulators (Deep Brain Stimulators) for Parkinsons Disease Obsessive Compulsive Disorder Depression Infusion pumps (diabetes) Artificial Hearts Metal rods to support broken bones Spinal stimulators Hearing aids

Medical ImplantsOne definition of implants is as having a minimum lifespan of 3 months, as penetrating living tissue, as having a physiologic interaction, and as being retrievable. There is no tracking for medical implant devices (MIDs), but NIH says they have been used widely for more than 40 years, and it is estimated that 8 percent to 10 percent of Americans (20-25 million people) currently have such a device.

Interference with Medical Implants Interference can: Prevent normal therapeutic function Reset or reprogram the device Bring damaging energy into the device or body Cause injury including death

EMI/RFI Any metal object can act as antenna If the metal is not the right size, shape and orientation, it will not be very efficient, but still an antenna

A metal tooth filling can be a radio receiver

The red DBS parts are metal

Medtronics Kinetra DBS Patient Manual Lists more than 16 pages of EMI warnings: Cardiac Defibrillators (1 kV), Diathermy and MRI Theft detectors and security gates (airports, schools, courts, libraries and retail stores) CB or ham radios, TV & radio transmitting towers Electric arc welding equipment Induction heaters and Industrial blast furnaces Power lines, electric substations and generators Cell phones

DBS and Diathermy EMI Shortwave, Microwave, or Ultrasonic Diathermy (deep heat treatment)

Energy from diathermy can be transferred through your implanted system, can cause tissue damage and can result in severe injury or death. Medtronics Kinetra neurostimulator patient manual

DBS and MRI RFI Performing MRI with this equipment can cause tissue lesions resulting in serious and permanent injury including coma, paralysis, or death. Medtronics Kinetra patient manual

DBS Pulse Parameters

Security Gates Walk through metal detectors up to 374,100 nT at 100-3,500 Hz (FDA) DBS programmer 80,000 nT at 130-185 Hz Airports, museums, courts, hospitals, schools, more

FDA Aware of ProblemElectro-Magnetic Interference from Security Systems In the late 1990s, CDRH identified over 100 reports of injuries to patients with critical active implanted medical devices such as pacemakers/defibrillators and nerve stimulators. Injuries often occurred when patients walked through some electromagnetic security devices like metal detectors.

Retail & Library Theft Detection Electronic Article Surveillance (EAS) Systems Up to 220,000 nT at 219 Hz (FDA) DBS programmer 80,000 nT at 130-185 Hz FDA has found 28 cardiac pacemakers, automatic implantable cardiac defibrillators (AICD), spinal stimulators, hearing aids and ambulatory infusion pumps have failed or malfunctioned in the presence of EAS systems

Dont always know theyre there

Radio, TV, Police Transmitters

Powerlines, Substations & Generators

Cell Phone Towers and Disguises

Cell Phones, PDAs, iPods

DBS Interference Not cited by Medtronics: -Wireless Inductive Chargers -Roadside Microwave Traffic Sensors -Electric Car Chargers -TASER (Neuro-musculature Incapacitation) -Active Denial System (Nonlethal Beam Weapon) (CSI:NY 28 Oct 2009) -Lightning

Wireless Inductive Chargers for cell phones, cameras, computers and toothbrushes

Roadside Microwave Traffic Detector

TASER 50,000 volts (50 times a cardiac defibrillator)

Active Denial System 96 GHz 100 kW microwave beam

Active Denial System aka Silent GuardianDeveloped by DoD for nonlethal crowd control On CSI:NY 28 Oct 2009 episode killed a man with a cardiac pacemaker In demand for ship antipiracy and by law enforcement personnel

Lightning Huge transient currents and magnetic fields NWS says only flash floods kill more people than lightning Literature reports lightning has reset DBS

National Lightning Safety Institute

Live in steel box or the Ocean Bottom

FDAFDA's Center for Devices and Radiological Health (CDRH) is responsible for regulating firms who manufacture, repackage, relabel, and/or import medical devices sold in the United States. In addition, CDRH regulates radiation-emitting electronic products (medical and non-medical) such as lasers, xray systems, ultrasound equipment, microwave ovens and color televisions. - FDA

FDA CDRHFDA regulates radiation emitting electronic products. The purpose is to prevent unnecessary exposure to radiation due to the use of these products. There are specific requirements that apply to all radiation emitting electronic products in order to comply with the provisions of the Food, Drug and Cosmetic Act. If the product is also a medical device, the product must also comply with the medical device regulations.

FDA CDRH

The term "electronic product radiation" means any ionizing or non-ionizing electromagnetic or particulate radiation, or any sonic, infrasonic, or ultrasonic wave

FDA Aware of Problem 1996 FDA Science Forum Poster Abstract: A-46 From the 1996 FDA Science Forum. Abstract # A-46. Survey of Several Electronic Article Surveillance Systems for the Potential for Electromagnetic Interference. ... www.accessdata.fda.gov/ScienceForums/forum96/A-46.htm - 3k - Cached 2002 FDA Science Forum Poster Abstract: U-03 Board U-03. Medical Device Malfunctions Due to Electromagnetic Interference from Metal Detectors: FDA Concerns and Work Toward Solutions ... www.accessdata.fda.gov/ScienceForums/forum02/U-03.htm - 3k - Cached 2005 FDA Science Forum Poster Abstract: L-06 ... Background: FDA is concerned that the emissions from some wireless PDAs may cause electromagnetic interference (EMI) in nearby active medical devices. ... www.accessdata.fda.gov/ScienceForums/forum05/L-06.htm - 3k - 2008-12-23 Cached Interference with Pacemakers and Other Medical Devices ... Radiofrequency energy (RF) from cell phones can interact with some electronic devices. This type of interference is called electromagnetic interference (EMI). ... www.fda.gov/.../HomeBusinessandEntertainment/CellPhones/ucm116311.htm 32k - Cached

Guterman et al., IEEE APS Trans., vol 51, n. 4, p.12-39 (August 2009)

What WiFi antenna in laptops do to the human body, but not what they do to medical implants.

Cell phones & Hearing aids

Yang et al., IEEE APS, v.50, n.3, p.51-65 (June 2008)

Very Few Studies

and not in the US Sweden and Lebanon

You have to askWhy is so little known? (about something that has the potential to injure or kill more than 20 million Americans)