Tomographic method of x-ray imaging
First Claim
1. A method for determining a three-dimensional density, distribution among volume elements in a volume containing at least one material, the method comprising:
- a. producing a beam of energetic photons for penetrating the volume;
b. scanning the beam sequentially across incremental positions of the volume in a plurality, of paths having substantially parallel directions separated by incremental steps;
c. detecting scattered photons of substantially all energies scattered by the material in said volume with a detector having a spatial resolution in a direction substantially parallel to the paths of the beam;
d. measuring the intensity of scattered photons scattered approximately perpendicular to each substantially parallel direction of the beam at each incremental position of the beam to derive an independent measurement of intensity, of scattered photons scattered from the volume elements in the volume;
e. identifying a volume element as the approximate origin of scattering along the path of the beam giving rise to the measurement of intensity of scattered photons; and
f. calculating an independent density for each volume element of the material in the volume.
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Accused Products
Abstract
A method is disclosed for obtaining the density distributions of three-dimensional elements that compose objects or groups of objects, by examining the objects with beams of x-rays or gamma radiation that are transmitted through the object in a plurality of approximately parallel paths and measuring the intensity of the radiation, scattered approximately perpendicular to the parallel paths, in arrays of detectors around the object. The energy of the x-rays or gamma rays is such that dominant interaction in the object is Compton scattering. The density of each element is determined from the totality of measurements by standard mathematical tomographic or relaxation techniques of data manipulation.
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Citations
17 Claims
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1. A method for determining a three-dimensional density, distribution among volume elements in a volume containing at least one material, the method comprising:
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a. producing a beam of energetic photons for penetrating the volume; b. scanning the beam sequentially across incremental positions of the volume in a plurality, of paths having substantially parallel directions separated by incremental steps; c. detecting scattered photons of substantially all energies scattered by the material in said volume with a detector having a spatial resolution in a direction substantially parallel to the paths of the beam; d. measuring the intensity of scattered photons scattered approximately perpendicular to each substantially parallel direction of the beam at each incremental position of the beam to derive an independent measurement of intensity, of scattered photons scattered from the volume elements in the volume; e. identifying a volume element as the approximate origin of scattering along the path of the beam giving rise to the measurement of intensity of scattered photons; and f. calculating an independent density for each volume element of the material in the volume. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A device for determining densities in volume elements in a material present in an assembly of objects, the device comprising:
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a. a source for producing a beam of energetic photons having a direction for penetrating the material; b. an arrangement for scanning the beam of energetic photons in a sequence of sequential beams across the assembly in a manner such that successive directions of the sequential beams are substantially parallel to each other, the sequential beams passing through every volume of the assembly; c. a detector disposed substantially parallel to the direction of the beam of energetic photons for providing measurements of the intensity of scattered photons of substantially all energies scattered approximately perpendicular to the direction of the beam at each incremental position of the beam; and d. a computer for determining the densities in the volume elements of the material in the assembly from a totality of measurements of the intensity of scattered photons scattered approximately perpendicular to the direction of the beam at each incremental position of the beam by a mathematical reconstruction technique. - View Dependent Claims (12, 13, 14, 15, 16, 17)
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Specification