Figure 3

Dose-volume histogram (DVH) changes in planning target volume (PTV), total lung, and functional lung in a sample case. (a) DVH of an anatomic-constrained IMRT treatment plan with five equally-spaced beam arrangements (solid lines) and five manual optimization beam arrangements (broken lines). (b) DVH changes are also shown in a functional-constrained IMRT plan using highly functional lung as an avoidance structure with different beam arrangements.