Abstract

Radio-frequency (RF) electromagnetic field (EMF) exposure assessments can be divided into two categories: 1) incident field assessment, i.e., the quantification of the incident EMF or the field characteristics at the location of the exposed bodies without their presence (plane-wave equivalent), and 2) dosimetry, i.e., the quantification of the EMF induced in the biological tissues of a human. The dosimetric quantity above 10 MHz associated with biological effects as determined by the standardization bodies (e.g., ANSI/IEEE, ICNIRP, NCRP) are the whole-body averaged and peak spatial specific absorption rates (wbSAR, psSAR), expressed in units of W/kg. Below 100kHz, the safety limits are defined in terms of induced fields and current density.  Between 100 kHz and 10 MHz both dosimetric concepts must be considered.  Highly accurate, individually-based exposure predictions are required for medical applications, such as hyperthermia, as well as for biological in vivo and in vitro experiments. Reliable estimates of the exposure of specific user groups are required for epidemiological studies aimed at correlating human exposure to EMF with possible health effects.  

In compliance evaluation, reliable demonstration that the actual exposure is below the safety limits for a certain population coverage is the key objective (e.g. IEEE 1528, IEC 62209, etc.). For most sources that do not operate in the close vicinity of the body, compliance can be reliably and conclusively  demonstrated by simple incident field measurements. The strongest exposures of human tissue, however, result from hand-held and body-mounted devices. 

The exponential growth of mobile communication technologies and their usage by more than 4 billion users worldwide has increased the RF exposure of the average person by several degrees of magnitude. The quality of the exposure is also changing due to the continually evolving technologies, and therefore new concerns are constantly being raised about the potential health risks associated with these applications.

Research has been divided into the following two areas to address these health concerns:

- general dosimetry and compliance testing with respect to SAR and induced fields

- biological research to support risk evaluations

Due to the substantial funding allocated to these two research areas by government and industry, impressive progress has been achieved during the last 15 years. Compliance testing became a worldwide standard for mobile devices with uncertainties of less than 20%, and in addition, installation rules have also been developed to reduce the average and maximum exposures. These procedures are based on a fundamental knowledge of the mechanisms of interaction, novel instrumentation (scanners, probes, phantoms, tissue simulating materials) and novel computational  codes. Future trends indicate that both measurement and simulation need to be applied for demonstrating compliance. The literature on studies related to risk assessment has been significantly expanded, now including epidemiological, human volunteer, in vivo and in vitro studies. 

In my talk, I will discuss the achievements during the last decade, the current state-of-the-art, and identify current shortcomings and open issues to be addressed in the future. Although some of the shortcomings are due to the inevitable consequence of struggling to keep pace with the quickly evolving new and complex wireless technologies that significantly change the human exposures, other challenges are due to the publication of scientifically unexplainable findings. Another focus will be on how to avoid the mistakes of the past.

Biodata

Professor Niels Kuster received his MS and PhD degrees in Electrical Engineering from the Swiss Federal Institute of Technology (ETH) in Zurich. In 1993, he was elected Professor at the Department of Electrical Engineering of ETHZ. He has also served as the founding Director of the Foundation for Research on Information Technologies in Society (IT'IS), Switzerland since its inception in 1999. During his career he has held invited professorships at the Electromagnetics Laboratory of Motorola, Inc, Florida, and at the Metropolitan University in Tokyo, Japan in 1998. In addition, he is a founding member of Schmid & Partner Engineering AG (1993), MaxWave AG (1999), NFT (2001) and Zurich Med Tech (2006).

His primary research interests are in the safe and beneficial applications of electromagnetic fields in health and information technologies. He is particularly interested in 1) measurement technology; 2) computational electrodynamics for the evaluation of close near-fields in complex environments (e.g., handheld or body-mounted transceivers, residential/work environments, etc.); 3) safe and reliable wireless communication links within the body or between implanted devices and exterior equipment for biometric applications; 4) development of exposure setups and quality control for bioexperiments to evaluate interaction mechanisms, therapeutic effects and potential health risks; 5) exposure assessments; 6) EM safety of medical devices; 7) medical diagnostic and therapeutic applications of EM, in particular EM cancer treatment modalities; and 8) virtual patient applications. He is currently building up a new research team in computational life science.

Niels has published more than 500 publications (books, journals and proceedings) on measurement techniques, computational electromagnetics, dosimetry, exposure assessments and bioexperiments. He is a member of several standardization bodies and consults government agencies around the globe on the safety of mobile communications. He also serves on the boards of various scientific societies and journals. He is the current Past President of The Bioelectromagnetics Society, Associate Editor of IEEE Transactions on Electromagnetic Compatibility and an Editorial Board member of Bioelectromagnetics.