The attenuation of ultrasound in biological fluids

We have measured the ultrasonic attenuation parameters alpha o and n of several biological fluids in vitro in the frequency range 2.8-6.8 MHz, using frequency shift and/or a sinc (.) sidelobe ratio technique. The parameters alpha 0 and n describe the frequency-dependent attenuation via a power-law model, i.e., alpha(f) = alpha 0 fn, where f is frequency. The samples investigated were blood, pus, cyst fluid, bile, and infected hematoma. It was found that the values of alpha o span approximately the range between 0.03-0.3 dB cm-1 MHz-n, and values of n range from about 1.1-1.3.