Physical Mechanisms for Biological Effects of Ultrasound at Low-Intensity Levels

Abstract

Much of the recent increased interest in bioeffects of ultrasound stems from the astounding success of ultrasound in diagnostic medicine. Because it is so widely used in examining pregnancies, it is now to be expected that much of the future population of the world will have been exposed to ultrasound before birth. As the societal impact of any environmental agent increases, so does public concern about its safety. Hence it is not surprising that questions are being raised from various quarters about possible risks from medical ultrasound, even though its safety record is excellent. It is necessary to respond to these questions now, and continuously, although most of us would very likely prefer to have more knowledge before passing judgements. In order to respond, a number of individuals and groups have turned to the scientific literature for help and have sought to form conclusions based on the published data. In Fig. 1. is a generalization arrived at by the Bioeffects Committee of the American Institute of Ultrasound in Medicine (AIUM). It was approved by the AIUM in 1976 and again, slightly revised, in 1978.