Corrections for X-Ray Polychromaticity Effects on Three-Dimensional Reconstruction

The effect of polychromaticity on the reconstruction of attenuation coefficients from X-ray transmissions is presented by computer simulations of two simple phantoms. The distortions resulting from different amounts of X-ray beam hardening along different paths can be reduced by an equivalent water path analysis and a two parameter energy independent analysis. The first method transforms the projected paths into equivalent (i.e., same total transmission) water path lengths. The second method uses two spectra to factor out the energy independent parts of the photoelectric and Compton coefficients. This solution also involves conversion into equivalent water path lengths.