Numerical indicators of nonlinear propagation in acoustic fields

Measurements of acoustic exposure made in water and then derated to account for the attenuation of tissue can be distorted by nonlinear effects. We have evaluated numerical indicators of such distortion in diagnostic ultrasound fields.We evaluate the indicators of the degree of nonlinearity in diagnostic ultrasound fields that could be used to guarantee 'quasi-linearity' or to correct measurements made under nonlinear conditions. A new indicator, σi, is introduced which can be calculated using measurements currently being made in ultrasound test labs