Target migration from re-inflation of adjacent atelectasis during lung stereotactic body radiotherapy

Figure 1 Computed tomography simulation including a four-dimensional and free-breathing computed tomography. A: Computed tomography (CT) images at simulation (left to right; axial, sagittal, and coronal views) showing the tumor, treatment isocenter, and the adjacent segmental atelectasis (best pictured on coronal image, lateral to isocenter); B: Left panel shows the tumor enclosed within the planning target volume (PTV) on the initial simulation CT; right panel demonstrates the translocation as compared with the original PTV on the re-CT after the first fraction. Sagittal views are shown in both panels; C: Dose distribution of initial (left) and translocated (right) tumor with isodose line values provided on left. Sagittal views are shown in both panels.