Naslov
An investigation of the use of the doppler technique to study acoustic streaming in biological fluids

Autori
Žauhar, Gordana ; Starritt, Hazel ; Duck, Francis

Izvornik
Physica Medica (1120-1797) 12 (1996), 3; 197-197

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
streamig; ultrasound; blood; doppler

Sažetak
There has been little investigation of acoustic streaming generated by diagnostic ultrasound fields. It is an important area for study both for safety reasons and because it has potential application as a diagnostic tool. A method of investigating streaming in biological fluids is reported. A number of fluids were insonated using a 3.5 MHz single element transducer which was driven in pulsed mode with a total acoustic power of 150 mW. Streaming was detected in each fluid using an 8 MHz continuous wave Doppler system and the maximum streaming velocity was obtained by spectral analysis of the Doppler signal. Using this system streaming was observed in water and 4.5% human serum albumen (HSA) solution, to both of which sephadex had been added as a scattering material, and also in blood. Each fluid was contained in a polyethylene bag and suspended in a water-bath in the acoustic beam. There was a 3 cm fluid path within each of the fluids under investigation and the water path, from the transducer to the sample fluid, varied in the range 2 cm to 13 cm. Longitudinal streaming profiles were measured and the maximum streaming velocities detected were: 8.2 cms-1 in water, 5.8 cms-1 In HSA and 4.7 cms-1 in blood. Streaming was also observed to occur in these fluids using a modern commercial Duplex scanner operating in pulsed Doppler mode. In this case the pulsed Doppler beam was used both to induce a stream and to detect it.The dependence of streaming velocity on viscosity, ultrasonic absorption and non linear effects is considered in the light of the results presented. The observation that streaming values were greatest in water in spite of its low attenuation, was attributed to the high degree of nonlinearity. Streaming in blood was found to be less dependent on pulse amplitude. In addition the relative merits of the Doppler technique, in comparison with other techniques for investigated acoustic streaming, are discussed.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

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