2 Numerical Modeling for Assessment and Design of Ultrasound Vibroacoustography Systems

Ultrasound vibroacoustography is a new medical imaging technique that relies on the nonlinear interaction of high-frequency fields to produce a low-frequency acoustic emission. Combining the resolution obtained by using a high-frequency focused source with the clean (free of artifacts from multiple scattering) images obtained with low-frequency fields yields a clearer image of abnormal tissue than does traditional ultrasound. A modeling strategy for this imaging modality is presented that overcomes the traditional difficulties in modeling over the range of frequencies present in these experiments. Through a combination of appropriate approximations and exact methods, it is possible to obtain images that capture the basic structure of experimental data despite the use of a simplified physical model.