Answer to Question #8460 Submitted to "Ask the Experts"

Category: Consumer Products

The following question was answered by an expert in the appropriate field:

Q

I am a diagnostic medical physicist and had someone ask me if hearing aids could be affected by radiation. She was told by her physician, and apparently in the instructions of the device, that the units could be adversely affected by exposure to radiation. I have never come across such information. Is there data or information that could lead to such a claim? The hearing aids were apparently a special, custom-made type of device. I did not see the instructions personally; these were questions from the user of the aids. Any information would be much appreciated.


A

If there is a safety issue, the hearing aid manufacturer must identify it in its label. Most medical device manufacturers are aware of potential interference from radio frequency waves, magnetic fields, or even ionizing radiation.

Additionally, if there is any telemetry associated with the medical device, the transmission frequencies are regulated by the Federal Communications Commission. In general,  most medical devices are relatively insensitive to most radiations encountered in normal daily living, including most medical x-ray and even therapy machines. The one exception is magnetic resonance imaging (MRI), where the high magnetic fields will interfere with any magnetic objects. Users of such products are well aware of this.

Similar to ALARA, the policy of exposing individuals to radiation that is "as low as reasonably achievable," most manufacturers want to be prudent and simply may warn against "possible" interference, even if such information is lacking. For example, many medical product manufacturers may make a statement about using their products on pregnant women, yet pregnant women may never have been tested with their product. So the statement is not necessarily based on scientific data, but the lack of such data. I also suspect that product liability may sometimes be the driving force behind such statements, but I am not sure.

Let me relate a true experience. A few years ago some of the security screening devices that detect package theft from department stores were causing interference with some implanted medical devices. These were rare and unpredictable, but in fact were occurring. The position of some security screening manufacturers was that it was the device manufacturer's responsibility. The medical device manufacturers countered with the fact that these screening systems were hidden and patients would not necessarily know when they were near such a detector. Since the Food and Drug Administration (FDA) also has the authority to regulate any electronic product, it used its authority to simply discuss the topic at an advisory committee in the public forum. The security screening companies' lack of experience with FDA resulted in an unexpected but serious increase in their anxiety level. They believed, incorrectly, that FDA could ban their product. The public meeting was enlightening.

Many such manufacturers do test for electromagnetic field interference. If a transmitter or receiver is involved, they also have to comply with Federal Communications Commission regulations for the specific communication frequencies they may be using. Safety is factored into the product.

Obviously it can get pretty complicated, but the performance of their product is at stake, so they need to know. The information on the label and in the instructions is the definitive source of information for that specific product.

I am attaching several links to several organizations, some of which provide additional links, that might provide more information than you care for.

The Federal Communications Commission Web site provides answers to frequently asked questions. 

The Food and Drug Administration (FDA) Web site covers a broad range of such electromagnetic products.

The Department of Labor's Occupational Safety and Health Administration Web site provides some excellent information.

The Environmental Protection Agency has an excellent and informative site.

And finally, I refer you to our own Health Physics Society site. 

I hope this is useful information.

Orhan H. Suleiman, MS, PhD

Answer posted on 15 September 2009. The information posted on this web page is intended as general reference information only. Specific facts and circumstances may affect the applicability of concepts, materials, and information described herein. The information provided is not a substitute for professional advice and should not be relied upon in the absence of such professional advice. To the best of our knowledge, answers are correct at the time they are posted. Be advised that over time, requirements could change, new data could be made available, and Internet links could change, affecting the correctness of the answers. Answers are the professional opinions of the expert responding to each question; they do not necessarily represent the position of the Health Physics Society.