A Geometrical Acoustics based Focusing Algorithm for Layered Media in Medical Ultrasound

Abstract

Ultrasound imaging is a widely used, non-invasive diagnostic tool in modern medicine. A crucial assumption is a constant sound speed in the observed medium. For large scale sound speed variations, this assumption leads to blurred and distorted images. In this paper, we present a Geometrical Acoustics based Focusing Algorithm (GOAT) which is able to correct for these aberrations, given a known layered medium setting with continuously differentiable medium boundaries. Existence and uniqueness conditions for a solution to the underlying system of equations are given. Using numerical simulations, the precision of our method is evaluated. Finally, the resulting image quality improvements are demonstrated in a phantom-based experimental setup.