Reconstruction Algorithm for Sound Speed Distribution in the Female Breast

Abstract

- In the last few years, Ultrasound Computed Tomography (USCT) techniques has become an attractive and hot research area. Herein, we present a robust iterative USCT reconstruction algorithm, which based on bent ray theory. The object to be imaged is encircled by uniformly distributed transducers, whereas one transducer acts as a transmitter and the remains work as receivers. The travel-time measurements can be used to estimate the sound speed distribution by solving a nonlinear system of equations. Our proposed scheme is based on the straight ray approximation, which is valid for breast ultrasound tomographic imaging. On this basis, we have formulated a cost function that defines the difference between the measured first arrivals and those calculated for a given velocity model in the least squares sense. Then, the sound speed image can be obtained by finding the best solution which minimize this difference. Our method is able to resolve very fine details even in very complex structured objects. The presented results approve the accuracy and robustness of our approach for breast screening applications