Figure 1From: Volumetric modulated arc planning for lung stereotactic body radiotherapy using conventional and unflattened photon beams: a dosimetric comparison with 3D techniqueDue to the limitation that the gantry of a Varian accelerator cannot pass from 180° to -180° and vice versa, the ideal arcs (dashed arc in this example) often have to be shortened to be deliverable (solid arc).Back to article page