Influences of tissue composition and structural features of biological media on the ultrasonic nonlinearity parameter

The acoustic nonlinearity parameter is an important parameter in nonlinear acoustics.In this article,the nonlinearity parameter B/A of normal and eight kinds of pathological pig's liver tissues are measured by finite amplitude insert-substitution method.The mixture law for nonlinear parameter is used to analyze and predict the volume fractions of composition in a given tissue.It is found that the nonlinearity parameter is sensitive to the pathological state of biological:tissues and the values of B/A depend on the tissue compostion and structural features.