Medical ultrasound algorithm for noninvasive high intensity ultrasound applications

Thesis (Ph. D.)--University of Washington, 2001In order to simulate ultrasound propagation and subsequent thermal effects in biological media in which blood vessels and other structures may be present, a 3-dimensional model has been developed that eliminates the need for symmetry constraints.The model is based on the coupled solution of the full-wave nonlinear equation of sound in a lossy medium with the bioheat equation for temperature predictions. The algorithm includes nonlinear sound propagation, arbitrary frequency power laws for attenuation, is capable of treating material inhomogeneities and explicit modeling of large blood vessels. Unlike other models based on parabolic approximations, it is not restricted to near-axis solutions and can account for reflection and backscattered fields. The software is validated against known analytical solutions and in vitro experimental results in turkey breast. Very good agreement is found between experimental measurements and numerical prediction