August 10, 2001

Electromagnetic Research at NC State University Reveals Benefits and Risks of Microwave Technology

Three-dimensional model of a human
head showing colors that indicate
different SAR levels.

Electromagnetic technology provides numerous benefits, including cellular phones, radar, microwave ovens and medical diagnostic tools.  However, with any new technology comes the potential for unwanted side effects.  Some applications of electromagnetic energy are so new that researchers haven’t had time to study all possible impacts.  Now engineers at NC State University are working on projects that will explore potential uses of electromagnetic fields as well as characterize their possible negative effects.

Dr. Gianluca Lazzi, assistant professor of electrical and computer engineering at NC State, works in the field of bioelectromagnetics, or the study of electromagnetic effects on biological systems.  In this field computer models and mathematical calculations are used to investigate a variety of research questions, including studies of implantable medical devices, the safety of electromagnetic devices and sources of electrical malfunctions in the human body.

Part of Lazzi’s work involves using models to estimate the amount of power from a microwave device that penetrates human tissues.  According to Lazzi, “The applications for this study technique are extremely broad.”  Perfecting these techniques will help current and future researchers interpret microwave effects on biological systems.  Current techniques using computer models enable Lazzi and his research team to determine the specific absorption rate (SAR) of power per biological mass unit, which is measured in watts per kilogram (W/kg).  These models are being used in various projects.

For example, using a three-dimensional anatomically based model of a human head, Lazzi can calculate the SAR for a particular area of the head exposed to microwaves from a cellphone hypothetically placed on the ear of the model.  He can determine whether a selected one-gram cube of head tissue has an average SAR that is lower or higher than the American National Standard Institute (ANSI) established safety standard of 1.6 W/kg.  This standard, which is the foundation of the Institute of Electrical and Electronics Engineers (IEEE) and the Federal Communications Commission (FCC) safety standards, is based on past experiments in other laboratories that identified a minimum whole-body averaged SAR that induced some reversible behavioral disruption (task stoppage) in laboratory animals (4-8 W/kg).  “The current safety standard requires that the whole-body-averaged SAR be less than or equal to 0.08 W/kg for the general public, which is 50 times lower than the minimum level of discomfort and behavioral disruption exhibited in the animal model,” said Lazzi.  “Further, peak local SARs should not exceed 1.6 W/kg for any one gram of tissue in the shape of a cube, except for the hands, wrists and ankles where the peak one gram SAR should not exceed 4 W/kg.”

Lazzi’s team can produce an SAR number to determine how much power is absorbed by a given area of the brain, but what does that information mean?  According to Lazzi, “We are engineers so what we do is arrive at an estimation of actual electromagnetic conditions based on our models.  Then we need the help of biologists and medical doctors to provide answers to many bioelectromagnetic problems.”  Engineers can quantify and biologists may be able to qualify the effects, but no one knows yet what a given level of electromagnetic energy will mean to a biological system for all possible power levels and frequencies of the electromagnetic energy.

Thanks to Lazzi’s research, computer models for determination of the endogenous and exogenous electromagnetic fields of the human body are becoming more sophisticated all the time and are now able to provide information with details that were unthinkable only a few years ago.  Exciting future applications include use of Lazzi’s bioelectromagnetic techniques to design and test medical devices, such as retinal implants, brain implants and heart pacemakers. Someday Lazzi envisions that these medical devices could be also designed to send a signal from the patient to the doctor’s office, notifying the doctor when there’s a problem with the implant.  Devices could be designed to listen to the body’s own electrical signals as well, perhaps helping surgeons pinpoint electrical problems such as epilepsy in the brain.  “Anything we can do to understand the language of the body — its complex electrical signals — will help our knowledge advance,” said Lazzi.

Electromagnetic technologies are important and useful additions to our lives.  Current and future research will create broad applications for this technology as well as help researchers assess potential dangers and benefits to biological systems.

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Media Contacts:  Dr. Gianluca Lazzi, 919/513-3685, lazzi@eos.ncsu.edu, Linda E. Rudd, 919/515-3848, linda_rudd@ncsu.edu