A SURVEY OF THE ACOUSTIC OUTPUTS OF DIAGNOSTIC ULTRASOUND EQUIPMENT IN CURRENT CLINICAL USE

Surveys published up to 1991 have highlighted a steady increase in the acoustic outputs from diagnostic ultrasound equipment, Since 1991 we have made measurements of the maximum peak negative pressure (p-) and spatial peak temporal average intensity (I-SPTA) produced by 223 probe s from 82 scanning systems in current clinical use in the Northern Reg ion in the UK. Measurements have also been made of the maximum total a coustic power generated by 45 probes from 17 scanners, The results fro m these measurements are presented in this article and compared to the results of a similar survey of equipment from both the Northern and W essex Regions in the UK and published in 1991. The comparison shows th at measured I-SPTA values have increased approximately sixfold in B mo de and approximately threefold in colour Doppler mode. Also, measured total acoustic power values have doubled in pulsed Doppler mode. The p resent survey also draws attention to some particularly high I-SPTA va lues obtained from a number of probes and scanning systems, This surve y has shown that measurements of acoustic outputs from diagnostic ultr asound scanners in current clinical use are substantially higher than reported in earlier surveys and, for certain scanners, the acoustic ou tputs from scanned beam modes of operation can reach levels hitherto o nly found in pulsed Doppler mode.