G. Zauhar et al., STUDIES OF ACOUSTIC STREAMING IN BIOLOGICAL-FLUIDS WITH AN ULTRASOUNDDOPPLER TECHNIQUE, British journal of radiology, 71(843), 1998, pp. 297-302
Acoustic streaming generated by diagnostic ultrasound fields is an imp
ortant area for study both for safety reasons and because of its poten
tial application as a diagnostic tool. A method of investigating strea
ming in biological fluids is reported. A number of fluids were insonat
ed using a 3.5 MHz weakly focused single element transducer which was
driven in pulsed mode. Streaming was detected in each fluid using an a
MHz continuous wave Doppler system. The maximum streaming velocity wa
s obtained by spectral analysis of the Doppler signal. Using this syst
em longitudinal streaming profiles were measured. At an acoustic power
of 150 mW the maximum streaming velocities detected were: 9.3 cm s(-1
) in water, 6.8 cm s(-1) in 4.5% human serum albumin (HSA) solution an
d 4.9 cm s(-1) in blood, when transmission was through a water path of
approximately 10 cm into a 3 cm sample of fluid. When measurements we
re made in the biological fluids alone, without a water path, the maxi
mum streaming velocities were reduced.