The dose distributions (a) and dose-volume histograms (DVHs) (b) of a representative case.

(a) From left to right: 6-MV, 3-MV and the dual energy plans. From top to bottom: axial: sagittal, and coronal views. The isodose lines are 120% (purple), 105% (yellow), 100% (pink), 95% (light blue), 70% (green), 50% (orange), 40% (steel blue) and 20% (dark blue). Notable differences are marked by red arrows. (b) The 6-MV, 3-MV and dual energy plans are shown with thick lines, dashed lines and thin lines, respectively. The DVH curves for trachea, esophagus and skin are not shown due to very low dose level.