The Effect of Volume Fraction on the Backscatter from Nucleated Cells at High Frequencies
presentationposted on 21.05.2021, 16:25 by Ralph E. Baddour, Michael C. Kolios
Small variations in scatterer volume fraction, which can result from changes in tissue microstructure due to cancer therapies or organ preservation, may have a significant impact on ultrasound backscatter. Although the effect of volume fraction has been studied for non-biological scatterers and red blood cells, this study addresses the case of nucleated cells. Suspensions with volume fractions up to 70% of acute myeloid leukemia cells were insonified with broadband 20 MHz and 40 MHz pulses. The resultant average normalized backscatter intensities plotted as a function of volume fraction demonstrated a better agreement with the Yagi-Nakayama continuum scattering theory rather than the Mo-Cobbold particle scattering model (using hard sphere packing). Normalized backscatter increased with cell volume fraction up to a maximum value, occurring between 20 and 30% volume fraction, varying with frequency and then decreased with further increases in volume fraction. This result may have implications in the development of new quantitative, ultrasound-based tissue characterization techniques.