Compression paddle perimeter-breast support surface illustration. Various distances for the paddle perimeter assessments are illustrated with an arbitrary bulge. Adding 0.5 cm to the system compression thickness readout value, ts , gives the corrected height along the front edge of the breast support surface (left figure). The right figure shows the paddle tilt along the x-direction relative to ts. The paddle maximum bulge height (hm), located at (xm, ym) was estimated relative to paddle-perimeter height at × = xm for each of the phantom images that are summarized in Table 2.