Modeling nonlinear pressure fields in inhomogeneous attenuative media using a lossy Green's function and a contrast source

Attenuation or loss forms an important phenomenon in medical ultrasound. At ultrasonic frequencies, attenuation is mainly due to absorption. Experimental data reveal that attenuation acts according to a frequency power law. For a given penetration depth, this effect limits the frequency, and hence the attainable resolution, that is utilized in diagnostic ultrasound applications. Attenuation is also crucial for therapeutic applications where high intensity focused ultrasound fields are used for ablation and hyperthermia treatment. Modeling attenuative pressure fields in inhomogeneous media is therefore of great importance for the development of new ultrasound modalities and the optimization of treatment protocols. © 2011 IEEE.