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US 4,029,963 AGranted
X-ray spectral decomposition imaging system
AssigneeThe Board of Trustees of the Leland Stanford Junior University
InventorsRobert E. Alvarez, Albert Macovski
Life of this patent
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Abstract
Projection measurements are made of the transmitted x-ray beam in low and high energy regions. These are combined in a non-linear processor to produce atomic-number-dependent and density-dependent projection information. This information is used to provide cross-sectional images which are free of spectral-shift artifacts and completely define the specific material properties.
Claims22
Apparatus for providing energy-dependent x-ray images of an object comprising:
- an x-ray source positioned on one side of the object producing an x-ray beam which transverses the object;
- an x-ray detector positioned on the side of the object opposite that of the source;
- means for measuring the x-ray transmission through the object, with the x-ray detector, at the lower and higher energy regions of the diagnostic x-ray spectrum and producing a low-energy projection signal and a high-energy projection signal;
- computational means for processing the low-energy projection signal and the high-energy projection signal and producing an atomic-number-dependent signal which is substantially on the line integral of the atomic number of the object raised to a power, and a density-dependent signal which is substantially dependent on the line integral of the density of the object;
- and
- means for utilizing a plurality of the atomic-number-dependent signal and a plurality of the density-dependent signal to produce energy-dependent x-ray images of the object.
3 more elements
Apparatus for producing a cross-sectional x-ray image of an object comprising:
- a polychromatic x-ray source positioned on one side of the object producing an x-ray beam;
- an x-ray detector positioned on the side of the object opposite that of the source;
- means for measuring the x-ray transmission through the object with the x-ray detector at lower and higher energy regions of the diagnostic x-ray spectrum at a plurality of angles and producing a plurality of low-energy projection signals and a plurality of high-energy projection signals;
- computational means for processing each of the low-energy projection signals and high-energy projection signals to produce a plurality of processed signals which are the line integrals of an energy-dependent component;
- and
- means for utilizing the processed signals to reconstruct the cross-sectional image of the object which is free of spectral artifacts.
3 more elements
Dependencies are inferred from the claim text.