Figure 1.

Acrylic phantom simulating breast tissue and lesions of high attenuation (aluminum disks of different diameters and 1 mm thickness). Diameters of the disks of the first column (top to bottom): 5.0 mm, 4.0 mm, 3.0 mm, 2.0 mm, 1.0 mm, and 0.5 mm, respectively; Diameter of the disks of the second column (top to bottom): 4.0 mm, 2.0 mm, 0.5 mm, 1.0 mm, 3.0 mm, and 5.0 mm, respectively.