ABSTRACT. data which could be used in assessing the biological risk from exposure to ultrasonic energy. The system can reproduce the ultrasonic signals of medical diagnostic and therapeutic equipment at cmparable or greater intensities. Signal synthesis is at low electrical powers (<O dBm) with linear amplification of the signal to the desired level by a high power, broadband amplifier. minicomputer controls the exposure time and the net electrical power to the ultrasonic transducer assembly through an interface to a programmable frequency synthesizer. monitored by a dual directional coupler which, in turn, is monitored by the minicomputer with an r.f. digital voltmeter. controlled, water or saline filled exposure tank. tank serves as an ultrasonic absorber to minimize standing waves. measured by the bouyant float technique which is used to determine the ultrasonic transducer assembly efficiency of converting the net electrical power into ultrasonic power. hydrophone technique is used to obtain either axial or three dimensional perspective plots of the ultrasonic field. animal exposures such as 25 to 40 gram mice and liquid suspension exposures. An ultrasonic biological effect exposure system was developed to provide experimental A The net electrical power is The ultrasonic transducer assembly is mounted at one end of a temperature A castor oil load at the far end o f the exposure The total ultrasonic power is A scanning The exposure system can support two general types of experiments, viz., small -INTRODUCTION Even though the use of ultrasound continues to increase (Erikson yet to develop a reliable assessment of the risk associated with exposure to ultrassund (O'Brien 1972). One major reason i s that insufficient qualitative and quantitative information exists with respect to dose-effect relationships and interaction mechanisms (Reid and Sikov, 1972)
