ADVANCES IN ELECTROMAGNETIC FIELDS IN LIVING SYSTEMS Volume 3 ADVANCES IN ELECTROMAGNETIC FIELDS IN LIVING SYSTEMS Volume 3 Edited by James C. Lin University of Illinois at Chicago Chicago. Illinois Springer Science+Business Media, LLC The Library of Congress cataloged the fiest volume of this title as follows: Advances in electromagnetic fields in Iiving systems I edited by James C. Lin. p. cm. Includes bibliographicaI references and index. 1. Electromagnetic fields-PhysiologicaI effect. 2. Electromagnetic fields-Health aspects. 3. Electromagnetic fields-Therapeutic use. 1. Lin, James C. QP82.2.E43A29 1994 591.19'17-dc20 94-24263 CIP ISBN 978-1-4613-6886-1 ISBN 978-1-4615-4203-2 (eBook) DOI 10.1007/978-1-4615-4203-2 ©2000 Springer Science+Business Media New York OriginaIly published by Kluwer Academic / Plenum Publishees in 2000 Softcover reprint of the hardcover 1s t edition 2000 http://www.wkap.nl! 10 9 8 7 6 5 4 3 2 1 A c.I.P. record for this book is available from the Library of Congress Ali rights reserved No part of this book may be reproduced, stored in a retrievaI system, or transmitted in any form or by any means, electronic, mechanicaI, photocopying, microfilming, recording, or otherwise, without written permission from the Publisher PREFACE TO VOLUME 1 Hardly any phenomenon in the modern environment is as ubiquitous as electromagnetic fields and waves. We have learned to understand the physical characteristics of these energy forms, and we have applied them in abundant ways to embellish our ways of life and our stan- dards of living. Furthermore, we have come to depend on them for health, safety, information, comfort, and conveyance. Apart from their intended roles, these electromagnetic fields and waves produce other effects that may influence the activities of living organisms. The effects produced depend on many physical, chemieal, and biological factors. They may be grossly apparent and visible soon after exposure of the living organism or they may not appear to have influenced the organism at all upon casual examination. Even then, there may be subtle changes that are only detectable upon careful chemical or microscopic study, or which are apparent only after a considerable time delay. Nevertheless, our understanding of the interaction of electromagnetic fields with living systems is advancing in a wide range of topical areas. This bi-annual series with invited re- views by recognized leaders in their respective specialties, will present progress to date in key areas of research and scholarship. The guiding philosophy of this undertaking is the presenta- tion of integrated, known, and confirmed phenomenological observations, basic mechanisms of interactions, and applications in biology ilnd medicine, as well as perspectives on current topics of interest. A further intent of this series is to promote the interchange of ideas between biomedical, engineering, and physical science specialties, and thus the series is aimed at both practitioners and researchers. As the numbers of publications multiply, it becomes a challenge to locate and especially digest such a collection of papers, contradictions, and interpretations. It is hoped that volumes in this series will provide the catalyst in efforts to perfect our knowledge for health protection, and to develop new and better diagnostic, as well as therapeutic, procedures. In the last two decades, research on the biological effects and health implications of electromagnetic fields not only has expanded, but also has become a subject of a public con- cern and private debate, worldwide. This series is aimed at bringing together contemporary advances in key areas of research and scholarship. Very seldom can advances be totally divorced from past accomplishments. Accordingly, this premier volume begins with a chapter that discusses, briefly, contributions made by some of the early investigators on the interaction of electromagnetic fields with living systems. The interaction of radiofrequency (RF) electro- magnetic fields with the central nervous system has been a subject of considerable contempo- rary interest, since the nervous system integrates and regulates an organism's response to its environment. The chapter that follows summarizes the known effects of RF radiation on the v central nervous system and includes a review of interaction of RF exposure with psychoactive drugs on animals. The latter has become one of the most intriguing research subjects with profound implications for health effects and safety protection. This volume presents basic, applied, and clinical information ranging from extremely low to super high frequencies. In general, the interaction of electromagnetic fields and waves with biological systems is frequency-dependent. Moreover. the mechanisms of interaction for fields at low frequencies are very different from those at high frequencies. While significant ad- vances are being made on many fronts. a particular emphasis of this volume has been placed on the recent developments of our understanding in the very low and extremely low frequen- cies. They have led to some exciting new applications in the clinical management of tissue injury from exposure to extremely low frequency electric fields, and in the therapeutic treatment of.the musculoskeletal systems such as the repair of soft tissue wounds and bone fractures using low frequency fields (see Chapters 3 and 4). These low frequency fields also are emitted by circuitry within video display terminals (VDTs) and video display units (VDUs). Recently, considerable concern has been expressed by the public and some professionals about the possible health effects resulting from extended use of these devices. Chapter 5 examines, in detail, the possible effects of electric and magnetic fields from VDTs and VDUs on human health. It is my pleasure to acknowledge the National Science Foundation, Office of Naval Research, and the National Institutes of Health, for their support of my research throughout the years. Some of the results are found in various parts of this volume. A portion of the writing and editorial activities was completed while on sabbatical leave of absence from the Univer- sity of Illinois. I am grateful to the National Science Council of ROC on Taiwan, for the opportunity to serve as an NSC Chair Professor during the 1993-94 academic year. Many individuals have contributed to the realization of this volume. I want to thank especially, Mr. L. S. Marchand, the senior editor at Plenum, for his encouragement and patience through all phases of this work. I wish to express my appreciations to the authors for their friendship and willingness to share their intellectual accomplishments. And lastly, but importantly, to my family: my wife, Mei, and children, Janet, Theodore and Erik. I am deeply indebted for their faith. love, patience, and ungrudging support. James C. Lin Chicago and Taiwan vi PREFACE TO VOLUME 2 This is the second volume in the series on Advances in Electromagnetic Fields in Living Systems. The objective ofthis volume is to add to thescientific and professional litera- ture a number of significant pieces of research larger in scope than journal articles. We hope that this form of publication will make the information readily available to research organiza- tions, libraries, government agencies, independent investigators, and interested persons. The chapters in this volume are organized into two consecutive sets using two specific regions of the electromagnetic spectrum: extremely low frequency fields and radiofrequency radiation. While significant advances are being made on both fronts, greater emphasis of this volume is placed on recent developments at radio frequencies. Each chapter consists of a comprehensive review of a topic of current interest and growing importance. Much of the information is based on authors' own research and that of the contributions from investigators in the relevant scientific disciplines. The first two chapters of the book review two of the most significant topics that have played pivotal roles in raising and addressing the question of whether extremely low frequency (ELF) electric and magnetic fields can affect the development of cancer. Chapter I scrutinizes the connection between exposure to ELF electric and magnetic fields and melatonin synthesis or utilization. It examines data that have been reported to indicate that exposure of animals to ELF fields reduces the ability of these animals to produce this hormone. And it discusses the significance of the findings relative to the incidence of cancer in humans exposed to ELF fields. The large number of epidemiological reports that focus on cancer and its potential association with ELF exposure are evaluated in Chapter 2. It provides a strength evaluation for the available evidence at this time and a discussion on the unique challenges that face epidemiological studies of ELF exposure. An important task in assessing health risk from exposure to ELF and radiofrequency (RF) electromagnetic fields is the quantitative determination of ELF and RF fields within and without biological bodies. The emphasis of Chapter 3 is on computational methods for dosimetry and exposure assessment and their application in bioelectromagnetic investigations. It provides a general knowledge base for ,computational bioelectromagnetics. It also gives specific guides to computing ELF and RF coupling and field distributions inside homogeneous and nonhomogeneous phantom and animal bodies. The biological effects of RF and microwave radiation have become a focal point of attention because of the accelerated use of RF radiation for wireless communication over the past few years. Wireless communication systems use low power modulated forms of RF and microwave radiation that were not investigated extensively in the past. Research addressing issues pertaining to the wireless communication spectra has begun only recently. Chapter 4 vii summarizes results from published studies using frequencies in the same spectral band and provides information on current research activity. It includes carcinogenesis and cancer pro- motion by RF and microwave exposure, and other in vitro and in vivo experimental studies that involve primarily the central nervous system and other tissues in the head. A brief description of epidemiological studies on RF and microwave exposure is also inlcuded. The material should be of use for preliminary risk assessment. Chapter 5 examines, in detail, the reported experimental evidence for possible effects of RF fields on cancer initiation, promotion, and progression. It provides a necessary background for the direction of future laboratory research to help clarify whether RF and microwave radiation influences cancer initiation and development. It examines the critical parameters of the exposure that may account for any influence. An exciting new medical application, the clinical management of cardiac arrhythmia using catheter-delivered RF and microwave en- ergy, is summarized in Chapter 6. RF cardiac ablation has become the most commonly used minimally invasive procedure for treatment of irregular heart rhythm. Microwave energy is a viable alternative energy source for percutaneous catheter ablation (additional references to this energy source are give at the end of Chapter 4). While the health effects ofRF and microwave radiation remain a concern to the general public and many professionals, the new ANSIIIEEE exposure standard represents a wealth of scientific understanding and significant improvement over its predecessor. However, its com- plexity has caused difficulties in the implementation of the standard in the real world exposure situation. Chapter 7 provides guidance on what is involved in assessing exposure and offers insights to applying the standard from a practical perspective. Lastly, I wish to thank the authors for their important contributions. I also want to pay a special tribute to the investigators in this field. whose published works and personal communi- cations greatly helped us in writing the chapters. As always. lowe a huge dose of gratitude to my family for their faith and support. James C. Lin Chicago viii PREFACE TO VOLUME 3 The past few years have been exceptionally active periods for research on the interaction of electromagnetic fields with living systems. The subject has become a focus of attention because of the expansion of electric power use and distribution at 50 and 60 Hz in the extremely low frequency (ELF) spectrum between 3 Hz and 3kHz and because of the accelerated use of radio frequency (RF) radiation (300 MHz to 6 GHz) for wireless devices over the past decade. In addition to the primary intended roles, electromagnetic energy may produce effects that could influence the vital activities of living organisms. A major research effort related to possible adverse health effects of environmental electric and magnetic fields (EMF) was completed in the United States. A report, summarizing the research, was issued by the administering agency, the National Institute of Environmental Health Sciences [NIEHS, 1999]. Another report, appraising the research, was issued by the National Academy of Sciences [NASfNRC, 1999]. In. the summary report, NIEHS concluded that "the scientific evidence suggesting that ELF-EMF exposures pose any health risk is weak. The strongest evidence for health effects comes from associations obse~ved in human populations with two forms of cancer: childhood leukemia and chronic lymphocytic leukemia in occupationally exposed adults. While the support from individual studies is weak, the epidemiological studies demonstrate, for some methods of measuring exposure, a fairly consistent pattern of a small, increased risk with increasing exposure that is somewhat weaker for chronic lymphocytic leukemia t.han for child- hood leukemia. In contrast, the mechanistic studies and the animal toxicology literature fail to demonstrate any consistent pattern across studies although sporadic findings of biological effects (including increased cancers in animals) have been reported. No indication of increased leukemia in experimental animals has been observed." The National Academy of Sciences' review and evaluation concluded that results, from the research that was authorized by Congress, "do not support the contention that the use of electricity poses a major unrecognized public health danger." Moreover, the report stated that, "The biologic research contributed little evidence to support the hypothesis that a link exists between MF (magnetic field) and cancer." However, the report went on to state that, "In contrast with laboratory research, some epidemiological studies have reported difference in incidences of cancer associated with MF exposure that differs by as little as 0.2 to 0.4 J.L T." It is interesting to note that these two reports reached a similar conclusion-there is a need for further research, especially at the basic science level. This volume begins with a chapter describing the difference in coupling of ELF fields and RF radiation into biological systems and mechanisms of interaction disclosed through the Maxwellian formulation. While ELF fields and RF radiation occupy the same known electro- ix magnetic spectrum, their mode of coupling into biological tissues and their mechanism of interaction can be very different. It is shown that electromagnetic energy at ELF and RF frequencies can be used to probe the body in different ways. These observations suggest that it is possible to deduce explanations for a broad range of biological interactions and reactions through an examination of the coupling mechanisms for ELF fields and RF radiation. The next four chapters present current and future biomedical applications of electromagnetic fields and RF radiation in diagnostic imaging and therapeutic treatment- The last two chapters are devoted to the biological effects of pulse RF radiation. Clinical evaluation of magnetic resonance imaging (MRI), which relies on constant and RF magnetic fields for its operation, had begun in the 1980s. Continued developments in instrumentation and applications since then have allowed MR! to become the diagnostic imaging modality of choice in many medical practices. Moreover, the dramatically reduced scanning time has accelerated and diversified medical applications of MRI in recent years. Applications that are curr~ntly under investigation include magnetic resonance angiography, perfusion and diffusion imaging, temperature mapping, and functional imaging. Chapter 2 reviews some of the techniques and applications of MR!, and introduces a novel tissue impedance MR! technique for the brain. Imaging electrical activity of the brain is a promising area of noninvasive biomedical application of low frequency electric field. Chapter 3 provides a state-of-the-art review of imaging brain electrical activity using scalp electroencephalo- grams (EEG). The chapter discusses some of the inverse imaging algorithms used for EEG spatial deconvolution imaging, namely cortical-potential imaging in a realistically shaped inhomogeneous head model. The use of low frequency electric fields to improve and help maintain functions of the living system is a dazzling topic. External electric fields applied to biological materials interact directly on free electric charges and dipoles. They may cause intermolecular transitions and intermolecular processes than can lead to structural reorganization of the cell membrane through the technique of electroporation and electropermeabiIization. The induced transient changes in membrane states have led to electric field pulse techniques to gain increasing importance in cellular and molecular biology. in gene technology. and in therapeutic medicine. Chapter 4 gives a detailed account of the electric field pulse techniques and in vivo applications of electropermeabilization in combination with chemotherapy or as a tool for gene transfec- tion. Likewise. a better understanding of the fundamental mechanisms of electric field induced tissue modification and injury could help to develop efficient therapeutic procedures and effective management tactics. Chapter 5 discusses the theory and experimental evidence concerning the effect of intense electric field on cell membrane proteins and membrane active transporters. The fact that pulsed RF radiation was used almost exclusively for radars meant that few people in the general population would have encountered exposure to pulsed RF radiation as a by-product of technological aids in their daily activity. The science and engineering of RF technology have expanded to the point that many types of devices have been developed using pulse RF energy to embellish our lives. Indeed. we have come to depend on the pulse RF energy for health, security, information, and entertainment. Moreover, recent developments in high peak power pulsed microwave systems have renewed interest in exploring potential biological effects of high peak power RF pulses. Currently, there are systems capable of delivering 100 gigawatt (GW) pulses to a transmitting antenna and establishing hundreds of kV/m peak E-field intensity in the beam path. However, we know very little about the safety aspects of high peak power, ultra-short RF signals. Chapter 6 preserUs an up-to-date review of the biological data available in the English language for pulsed RF fields. x