Method for obtaining and dual-energy processing of X-ray sinograms for identifying low-contrast ubstances in CT using sources with a continuous radiation spectrum

The article proposes and implements a method of dual-energy CT. The method allows the contrast-enhanced differentiation of one substance from another when substances have similar chemical compositions and densities. In this case, the use of standard dual-energy CT methods does not allow the unambiguous identification of the desired substance. This is because X-ray sources emit non-monochromatic radiation, and changes in object thickness lead to significant absorption of low-energy radiation. The article justifies the use of a design solution to reduce the influence of variable object thickness on the absorption of low-energy X-ray radiation. This allows dual-energy transformation to be performed not for CT slices but for sinograms obtained at different energy spectra of X-ray radiation. After reconstructing the dual-energy sinogram on a CT slice, the desired substance is unambiguously identified. The successful implementation of this method is demonstrated in the example of beryl particles embedded in muscovite. In CT slices obtained after reconstructing dual-energy sinograms, beryl particles with sizes as small as 1 mm are clearly distinguished with a total sample thickness of 30 mm.