The CIRS Model 002HN IMRT phantom is designed to address the complex issues surrounding commissioning and comparison of treatment planning systems and verification of individual patient plans and delivery. The CIRS 002HN phantom properly represents human head and neck anatomy in shape, proportion and structure as well as density. This enables thorough analysis of both the treatment planning and delivery systems. The phantom is constructed of proprietary tissue equivalent epoxy materials. Linear attenuations of the simulated tissues are within 1% of actual attenuation for bone and water from 50 keV to 25 MeV. The phantom is circular in shape, approximates the size of an average patient. Tissue equivalent interchangeable rod inserts for ionization chambers allow for point dose measurements in multiple planes in the phantom and film calibration.* The phantom also supports film dosimetry with not only standard radiographic films but also GafChromic? media. Additional inserts are available to support a variety of other detectors including TLD¡¯s, MOSFET, and diodes. The Model 002HN accommodates one Ready PackTM 10¡± x 12¡± films in transverse orientation, two radiochromic or radiographic 10 x 10 cm films in transverse orientation and a stack of thirteen radiochromic films pre-cut to 63.5 x 63.5 mm in three different orientations. The Model 002HN has an optional four Electron Density reference plugs which can be interchanged in five separate locations within the phantom. The surface of the phantom is etched with grooves to ensure proper orientation of the CT slices and accurate film to plan registration. An optional cranial bone ring is also available.