Statistical limitations in x-ray reconstructive tomography

Statistical fluctuations, or noise, in reconstructed tomograms are analyzed as a function of x-ray energy. The result is essentially constant for energies above 50 keV, assuming constant dose and spatial resolution, and is in close agreement with the actual performance of the EMI-Scanner (water-bag model). The noise is inversely proportional to the square of cell dimensions. For scanners without a water bag, the theoretical noise is approximately 30% less.