Fig. 2.

Alignment of the line ROI to record the CT number and attenuation profile curves. The CTP 404 module was used to record the CT number and attenuation profile curves of the high‐, moderate‐, and low‐signal objects. (a) The CT numbers of these objects for each reconstruction algorithm were recorded radially around the object centers at 1° intervals using a line region of interest (1 × 27 pixels, 5‐mm circle‐radius). (b) The attenuation profile curves of these objects for each reconstruction algorithm were recorded radially around the object centers at 1° intervals using a line region of interest (1 × 51 pixels, radius of the circle of 10 mm).