(a) Reconstructed and reoriented slices after 12 OSEM iterations and clinical levels of smoothing for Ell5mmFD (full dose, 5 mm diameter), Ell8.68mmULD (ultra‐low dose, 8.68 mm diameter), and Ell8.68mmFD (full dose, 8.68 mm diameter). (b) Polar maps are shown for smoothed Ellipsoid detector systems and NCAT phantom smoothed by the same amount. All (including smoothed NCAT) have the septal wall thinning (white arrow) as present for other geometries and reconstructions.7, 28 Note that the mapping procedure expands the base region, spreading out small artifacts. [Color figure can be viewed at wileyonlinelibrary.com]