Estimation of the tissue lesion induced by a transmitter with aluminium lens

Abstract

A virtual source model is developed to describe the nonlinear acoustic field generated by a transmitter with aluminium lens. This model assumes the geometry focal length of the virtual concave transducer to be equal to the acoustic focal length of the real transducer. Thus the acoustic field in the focal area can be accurately presented by that generated by the virtual source. This model in combination with the bio-heat equation is applied to the size estimation of tissue lesion created by high intensity focused ultrasound. A transmitter with aluminium lens is used to create tissue lesions for bovine livers in vitro under three different focal acoustic intensities of 7, 13.1, 25.4 kW/cm2. The predicted tissue lesion volumes coincide well with those previously reported measured results for 7 kw/cm2, but are smaller those in the measurement for 13.1 and 25.4 kW/cm2 owing to effect of vapor bubbles. © Published under licence by IOP Publishing Ltd.