Attenuation and backscatter measurements on Albunex

Albunex is an ultrasound contrast agent that has been used in echocardiography among other areas. This paper presents theoretical and experimental considerations on the physical properties of Albunex, particularly the attenuation and backscattering coefficients, which are absolute quantities. They were measured as a function of the frequency using four transducers, covering the range from 800 KHz to 11 MHz. For a normal batch of Albunex, the attenuation results show a resonance peak at a frequency of approximately 2.2 MHz while the backscatter results show an increase of the backscattering coefficient for frequencies up to approximately 4.0 MHz, and a relatively flat response beyond this frequency. The theoretical model considering elastic properties with an additional restoring force caused by the microsphere's shell agrees reasonably well with the experiments