Most breast cancers (85%) originate from the epithelium and develop first in the ductolobular structures. In screening procedures, the mammary epithelium should therefore be investigated first by the performing of an anatomically guided examination. For this purpose (mass screening, surgical guidance), we developed a two-dimensional anatomic phantom corresponding to an axial cross section of the ductolobular structures, which makes it possible to better understand the interactions between the breast composition and ultrasound. The various constitutive tissues were modeled as a random inhomogeneous continuum with density and sound speed fluctuations. Ultrasonic pulse propagation through the breast computer phantom was simulated using a finite element time domain method (the phantom can be used with other propagation codes). The simulated ductal echographic image is compared with the ductal tomographic (DT) reconstruction. The preliminary results obtained show that the DT method is more satisfactory in terms of both the contrast and the resolution.