Computational phantom(three dimension computer models of human body) are essential in estimating organ doses from various occupational radiation exposures and medical procedures. Mathematical phantoms use mathematical equations to describe the organs and tissues of human body and voxel phantoms are human models based on CT or MRI obtained from high resolution continuous scans of a single individual. Voxel phantoms are exactly matches with individual so obtained results on these phantoms are accurate while mathematical phantoms are most general and covering a range of age. In this study were investigated the effect of phantom type on neutron absorbed doses and neutron effective doses. For this aim, we compared the calculated results on ORNL adult phantom (Mathematical phantom) with VIPMAN (voxel phantom) for absorbed doses on 26 organs in monoenergetic neutron beams under six irradiation conditions: AP-PA-RLAT-LLAT-ROT and ISO. In addition, the obtained effective dose results compared with Asian voxel phantoms: TARO and HANAKO and also VIPMAN for whole body. MCNPX Monte Carlo code was used for this simulation. The results of this study indicates that influence of phantom type (mathematical or voxel models) are not important on the absorbed dose and the effective dose values. But the size of the phantom (VIPMAN versus ORNL) significantly affected on absorbed and effective doses in all irradiation geometries. These results are important because working with mathematical phantoms is simpler and much easier than the complex voxel phantoms.

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