Stereotactic body radiation therapy (SBRT) planning. (A) Cone beam computed tomographic scan of animal model, axial view (above), sagittal view (below, left), and coronal view (below, right), with simulation of radiation dose distribution around the treatment volume, beam angles (red lines), and static fields (flanking blue lines) using a 5 × 5–mm collimator. (B) Cumulative dose-volume histogram of tumor volume, normal lung tissue, and organs at risk. (C) Planning target volume (PTV), R100%, R50%, D2mm, and V20 values for each animal model compared with the Radiation Therapy Oncology Group (RTOG) 0813 conformality protocol. (A color version of this figure is available at www.redjournal.org.)