Fig. 12.

Projection images of the Catphan spatial resolution phantom (reconstructed images in Fig. 12) and pelvis sized Gammex electron density phantom (reconstructed images in Fig. 9). Only a zoomed in section of the Gammex phantom is shown, and hypointense object is the cortical bone insert. Row (a), raw projection: intensity reduction in 2D grid’s shadows is clearly visible. Row (b), flat-field corrected projection: Since residual scatter was not corrected, septal shadows are overcompensated, and appear as hyperintense lines. Row (c), scatter map: Residual scatter intensity as measured by the GSS method. Row (d), GSS Method: Residual scatter was subtracted from the raw projection, followed by flat-field correction.