9C-2 Reconstruction of Speed of Sound for a Correction of Transit Time in Full Angle Spatial Compounding

For full angle spatial compounding, an object is imaged in one plane from multiple aspect angles and the obtained images are superimposed in correct geometric orientation. Thus, information about the distribution of speed of sound inside the object is required for a correction of individual images with respect to transit time and refraction of the ultrasonic waves. In this paper, we present a method to reconstruct such a distribution by a filtered backprojection of echo data from a reflector positioned behind the object. Using the reconstructed distribution, individual ultrasound images were corrected by a ray tracing algorithm before spatial compounding. Here, refraction was only accounted for at the outer boundary of the object, while inside only transit time was corrected. In vitro analyses are presented that prove the applicability of this approach.