Refinement of Treatment Setup and Target Localization Accuracy Using Three-Dimensional Cone-Beam Computed Tomography for Stereotactic Body Radiotherapy

After localization based on superficial markings in patients undergoing SBRT, orthogonal kV imaging detects setup variations of approximately 3 to 4 mm in each direction. Cone-beam CT detects residual setup variations of approximately 2 to 3 mm.