Determination of the acoustic nonlinearity parameter in biological media from second-order harmonic component in echo signals

This paper presents two methods for determination of the acoustic nonlinearity parameter B/A for biological media by using ultrasound echo signals. One is to use the finite amplitude insert-substitution method via the second harmonic component in echo signals reflected from a high-reflectance interface. The other is to measure B/A via the second harmonic components in echo signals reflected from both the front and back interfaces of the sample. The nonlinearity parameter B/A values of some liquids and biological soft tissues are obtained using these two methods. The results coincide well with the B/A values presented in the literature.