Figure 3b. Original and simulated CT scans in an 8-year-old boy with abdominal pain. (a) Transverse contrast material–enhanced helical CT scan obtained with a tube current of 180 mAs demonstrates an inflamed appendix (arrow) in the right lower quadrant. (b) Simulated low-dose (20-mAs) scan at the same z-axis level as in a also demonstrates the inflamed appendix (arrow).