Fig. 3From: Evaluation of OAR dose sparing and plan robustness of beam-specific PTV in lung cancer IMRT treatmentThe example case’s CTV projection area with respect to the beam angle is shown in a. The selected beam angles (0°, 30°, 160°, 220°, and 290°) are indicated as green circles. The first and second maximum projection beam angles are indicated as red triangles; the axial slice view of the example case’s beams are shown in bBack to article page