The application of computed tomography techniques to imaging with transmitted and reflected ultrasound

An experimental system has been constructed, based upon conventional linear arrays, to obtain both reflection and transmission data. The transmission data has been used to reconstruct images of the speed of sound distribution within various targets. It has been shown that quantitative speed of sound images, showing good resolution, can be obtained with the reconstruction methods when (a) the attenuation within the target is low, and (b) the speed of sound variation across boundaries is low. These sound images have subsequently been used to correct registration artifacts in the equivalent reflection UCT images of the same targets. These corrected reflection UCT images show much improved resolution, reduced speckle, and ease of interpretation when compared to conventional real-time pulse-echo ultrasound images