ULTRASONIC TOMOGRAPHY OF BIOLOGICAL TISSUE

In this paper, quantitative tomographic reconstructions of biological tissue are presented. First, the experimental setup and a hybrid filte red backpropagation (FBP) technique are briefly described. Using this technique, which includes exact backpropagation of data prior to recon struction by means of the classical FBP algorithm, quantitative veloci ty maps of relatively large biological objects can be obtained. Since the FBP algorithm is based on a first-order scattering approximation, the deteriorating effects of higher-order scattering in diffraction to mography are also discussed. The higher-order scattering limits the si ze of the biological object to a few centimeters. (C) 1994 Academic Pr ess, Inc.