The CIRS Model 600 Anthropomorphic Torso Phantom is designed to provide an accurate simulation of an average torso (22 cm posterior-anterior thickness) for medical imaging and dosimetry applications. The epoxy materials used to fabricate the phantom provide optimal tissue simulation between the Diagnostic and Therapy energy range (40 keV to 20 MeV). Unlike other cross-sectional dosimetry phantoms, the Model 600 includes internal organ structures such as the lungs, heart, liver, kidneys, spleen and pancreas. All simulated organs match the tissue density of actual organs and can be clearly visualized. The lower portion of the phantom contains a soft bolus material simulating a mix of 30 percent adipose and 70 percent muscle tissue. Simulated muscle material layers the rib cage and vertebral column. The exterior envelope simulates a mix of 43 percent adipose and 57 percent muscle tissue.