Part I 1 Introduction.- 2 Anatomy and Physiopathology of Radiation-induced Damage to Organs at Risk.- Part II 3 Radiation Dose Constraints for Organs at Risk: Modeling Review and Importance of Delineation in Radiation Therapy.- 4 Volumetric Acquisition: Technical Notes.- Part III Image Gallery 5 Axial CT Radiological Anatomy (Brain, Head and Neck; Mediastinum; Abdomen; Pelvis).- 6 Digitally Reconstructed Radiographs (DRRs).