creation of a voxel phantom for premature babies - 035

A premature born child is expected to receive a larger than normal number of diagnostic X-rays. They are often subjected to a large number of exposures (i.e. for premature babies 30 exposures are common). For these patients this may lead to a significant radiation detriment as they are very sensitive to radiation. Knowledge of radiation dose is therefore necessary to justify exposures. To calculate doses delivered to the entire body and to specific organs computational models of the human anatomy are designed. To achieve a representation as close as possible to the anatomical properties a voxel phantom for a premature baby has been developed. A computational model of human anatomy is a mathematical representation of the human body. The first computational models are the 'mathematical' models. Equations for planes, spheres, cylinders, etc. were used to describe the organs. Those models resemble human anatomy only vaguely. Nowadays voxel models are being used. High resolution cross-sectional digital images of internal anatomy are used to create a three-dimensional representation of the shape, volume and composition of the human organs. After segmentation, the images were converted to a voxel-model with the help of commercially available software, Scan2MCNP. Scan2MCNP converts CT, MRI, and other scan data to an input file for the Monte Carlo transport programs MCNP and MCNPX. The voxel volumes for the model are 3.0 mm³ and correspond with the pixel sizes in the MRI images. To each organ (or grey value) a specific tissue composition was attributed in the MCNP input file. In this model the slice thickness was 3 mm. A more precise model could be created by using thinner slices. It would also be nice to have a female model and models for different weight classes. Those models can then be used to assess patient doses for premature babies