Figure 1. Overlay contour plot for the anteroposterior projection with 20 cm polymethylmethacrylate and a filtration of 4.5 mm Al. The default clinical settings — a tube potential of 77 kV and system speed 400 — can be found along the x-axis. The white area indicates possible settings that do not lead to a lower image quality or higher effective dose. Lower image quality figure (IQF) values indicate better image quality.