2G-4 Investigating the Effect of Cell Size on the Backscatter from Suspensions of Varying Volume Fractions

It is known that scatterer volume fraction is an important parameter affecting acoustic backscatter. In this study, we investigated the impact of cell size on the volume fraction effect for nucleated cells at high ultrasound frequencies. Suspensions with cell volume fractions (CVF, the proportion of the volume of interest occupied by cells) up to 70% of acute myeloid leukemia cells and prostate cancer cells were insonified at 20 and 40 MHz. For the smaller cells, the backscatter coefficient at both frequencies increased with CVF up to a maximum value occurring near 25% CVF and then decreased with further increases in CVF. For the larger cells, the peak in backscatter was inferred to be at higher CVFs for both 20 and 40 MHz. The results suggest that a continuum scattering model, rather than a particle-based model, is best suited for predicting the scattering from cell suspensions