P3A-2 Resolution Assessment of a 3D Ultrasound Computer Tomograph Using Ellipsoidal Backprojection

At Forschungszentrum Karlsruhe a 3D ultrasound computer tomograph (USCT) is currently under construction aimed at early breast cancer diagnosis. Ellipsoidal backprojection is applied to reconstruct 3D images. As USCT is a system used for imaging, there is a profound interest in analyzing the image resolution and image quality of this system, especially with respect to its system parameters such as number of the sensors, the geometry of the aperture, applied signal processing, etc. In this paper the results of first assessments of the resolution are presented. The resolution is evaluated in terms of the 2D full width at half maximum (2D FWHM) of the system's 3D point spread function (PSF). Slice images of 3D PSFs have been calculated to assess the spatial variability of the PSF within the current setup of the system. However, calculating these results is very time-consuming, thus an approximative approach for the analysis of the 3D PSF in XY and Z has been developed. This approach allows the analysis of the PSF while changing a variety of system parameters in real time. The long term goal of this project is the optimization of the system parameters with respect to the image quality