Variability of Four-Dimensional Computed Tomography Patient Models

To quantify the interfractional variability in lung tumor trajectory and mean position during the course of radiation therapy.Repeat four-dimensional (4D) cone-beam computed tomography (CBCT) scans (median, nine scans/patient) routinely acquired during the course of treatment were analyzed for 56 patients with lung cancer. Tumor motion was assessed by using local rigid registration of a region of interest in the 3D planning CT to each phase in...