During the last 35 years, there has been considerable develop ment and increase in the number of devices that emit nonionizing radiant energies. These energies such as radiofrequency including microwaves are used in all sectors of our society for military, industrial. telecommunications, medical, and consumer applications. This increase in sources of nonionizing radiant energies has resulted in growing interest on the part of government regulatory agencies, industrial and military physicians, research workers, clinicians, and environmentalists. Although there is information on biologic effects and potential hazards to man from exposure to microwave/radiofrequency energies, considerable confusion and misinformation has permeated not only the public press but also some scientific and technical publications. Because of the complexity of the interactions of nonionizing radiation in biological systems, an inter-disciplinary approach is necessary to assess and elucidate the problems that evolve as this field advances and as the use of these energies expands. It is important to maintain a proper perspective and assess realistically the biomedical effects of these radiant energies so that the worker or general public will not be unduly exposed nor will research, development and beneficial utilization of these energies be hampered or restricted by an undue concern for effects which may be nonexis tent or minimal in comparison to other environmental hazards."

The editors are pleased to present these Proceedings of the V Course of the "International School of Radiation Damage and Pro- tection" of the "E. Majorana Centre", held in Erice (Italy) in No- vember 1983. The lectures and discussions among leading scientists in various disciplines of physics, engineering, biophysics, cellular biology, physiology and medicine from 11 countries are included in this compilation. In this volume we have attempted to explore all aspects of the interaction of static and Extremely Low Frequency (ELF: 0-300 Hz) electric and magnetic fields with biological tissue, systems and whole organisms; we considered dosimetry and what is known or pre- sumed concerning basic interactions, responses from the cellular and molecular level to the whole organism. Discussions of medical appli- cations as well as epidemiologic investigations related to high volt- age transmission were held with critiques of methodologies used and recommendations for future approaches. Consideration was also given to the necessity and principles of setting protection standards for man and the environment. We believe this is the first attempt to put all this informa- tion together into one volume to provide perspective for understand- ing the influence of static and ELF electric and magnetic fields on biological systems. We hope our attempts were successful. Martino Grandolfo Sol M. Michaelson Alessandro Rindi v ACKNOWLEDGEMENTS This is the Fifth Course of the International School of Radia- tion Damage and Protection of the "Ettore Majorana" Centre for Sci- entific Culture directed by Professor A. Zichichi.

This volume contains the lectures presented at the International School of Radiation Damage and Protection at the "Ettore Majorana" Centre for Sci entific Culture in Erice, Italy, September 6-15, 1985. The sixth course of the School, entitled "Advances in Applications, Biological Effects, and Dosimetry of Ultrasound," provided an in-depth review of all facets of ultra sound interactions and their biological effects on living systems, allowing an assessment of the hazard potential of the various applications of ultra sound. Particular reference was made to possible health risks associated with medical ultrasound exposure since this use is by far the most prevalent. Since the initial application of ultrasound to submarine detection, medical diagnostic and therapeutic applications have become predominant over the past 20 years. The question of safety of this physical agent is an extremely important one. In many industrialized countries most pregnant women receive at least one diagnostic ultrasound examination before the birth of the child. Thus, potential hazards to the fetus are of prime concern. This problem has been aggravated by the fact that the medical diagnostic applications of ultrasound have far outpaced research efforts on biological effects. A further compounding factor of concern to clinicians and scientists has been the use of higher and higher intensities by the manufacturers of ultrasound equipment, particularly higher peak pulse intensities."