Evaluation of phase aberration correction for a 3D USCT using a ray trace based simulation

3D ultrasound computer tomography (3D USCT) promises reproducible high-resolution images for early detection of breast tumors. The KIT 3D USCT provides three different modalities (reflectivity, speed of sound, and attenuation) using 2041 transducers. In this setup, with a diameter of 26 cm and height of 17 cm, ultrasound can travel over long distances up to 52 cm. Phase aberrations (PA) due to speed of sound (SOS) variations inside the measuring object (water, different breast tissues) cause many pulses not to overlap in a distinct voxel for the coherent reflectivity reconstruction. Previous research showed that image quality can be increased significantly performing a PA correction. As no quantitative error assessment was done yet, a simulation based on ray tracing is used to quantify their image degradation caused by PA and the effects of the applied PA correction. This was done with the metrics contrast, resolution and displacement for different positions in the 3D USCT. Our work shows that PA correction significantly restores the image quality.