Cross-sectional imaging system using a polychromatic x-ray source
First Claim
1. An improved cross-sectionsl imaging apparatus of the type wherein a polychromatic x-ray beam is projected through a cross-section of an object at a plurality of angles and wherein the resultant transmitted beam is detected and applied to a reconstruction computer where the detected transmission data is used to reconstruct the density of the cross-section and the reconstructed image information is applied to a display, wherein the improvement comprises:
- means for detecting a plurality of x-ray transmission signals representing the intensity of different energy spectra of the transmitted polychromatic x-ray beam;
means for deriving the logarithm of each of the x-ray transmission signals; and
means for deriving a weighted sum of each of the logarithms of the x-ray transmission signals and applying the weighted sum signal to the reconstruction computer.
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Abstract
The transmitted polychromatic x-ray beam in a cross-sectional x-ray imaging system is applied to pulse-height discriminators for energy spectral analysis. Various regions of the energy spectrum are separately counted in order to provide an accurate reconstruction of the cross-sectional density which is independent of the different materials in the path of the transmitted x-ray beam. This same energy spectral information is used to create separate images representing the different materials in the cross section.
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Citations
12 Claims
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1. An improved cross-sectionsl imaging apparatus of the type wherein a polychromatic x-ray beam is projected through a cross-section of an object at a plurality of angles and wherein the resultant transmitted beam is detected and applied to a reconstruction computer where the detected transmission data is used to reconstruct the density of the cross-section and the reconstructed image information is applied to a display, wherein the improvement comprises:
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means for detecting a plurality of x-ray transmission signals representing the intensity of different energy spectra of the transmitted polychromatic x-ray beam; means for deriving the logarithm of each of the x-ray transmission signals; and means for deriving a weighted sum of each of the logarithms of the x-ray transmission signals and applying the weighted sum signal to the reconstruction computer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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Specification