Non-invasive stationary system for three-dimensional imaging of density fields using periodic flux modulation of compton-scattered gammas
First Claim
1. A three-dimensional image-generating device comprising:
- an external gamma radiation source configured to irradiate an inspected object with source gamma rays to generate a three-dimensional representation of said inspected object;
a modulating unit employing time-dependent nodal windows, each of said nodal windows configured to impose a different time modulation to encode gamma flux from said external gamma radiation source or Compton-scattered gamma rays from within the inspected object as at least one of said source gamma rays and said Compton-scattered gamma rays interact within said inspected object;
said modulating unit configured to identify scattering locations, by either modulating said source gamma rays or said Compton-scattered gamma rays as either said source gamma rays or said Compton-scattered gamma rays pass through said nodal windows of said modulating unit; and
a radiation detector configured to detect said Compton-scattered gamma rays scattered from within said inspected object.
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Accused Products
Abstract
A three-dimensional image-generating device is an inspection system incorporating three components: a radiation source, a modulating unit, and a radiation detector. All three components of the inspection system may be stationary. The radiation source irradiates an external inspected object with mono-energetic gamma rays. The modulating unit, used in conjunction with the unique energy-angle characteristics of the Compton scattering process, by encoding the gamma rays, enables the identification of the spatial origin of single-scattered gamma fluxes as they pass through the inspected object enroute to the detector. The radiation detector and the computerized processor identify gamma fluxes scattered from various locations within the inspected object. The three-dimensional distribution of scattering locations within the inspected object that produce the detected single-scattered gamma fluxes and their intensity is converted to a three-dimensional mass distribution as an image within the inspected object.
62 Citations
83 Claims
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1. A three-dimensional image-generating device comprising:
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an external gamma radiation source configured to irradiate an inspected object with source gamma rays to generate a three-dimensional representation of said inspected object; a modulating unit employing time-dependent nodal windows, each of said nodal windows configured to impose a different time modulation to encode gamma flux from said external gamma radiation source or Compton-scattered gamma rays from within the inspected object as at least one of said source gamma rays and said Compton-scattered gamma rays interact within said inspected object; said modulating unit configured to identify scattering locations, by either modulating said source gamma rays or said Compton-scattered gamma rays as either said source gamma rays or said Compton-scattered gamma rays pass through said nodal windows of said modulating unit; and a radiation detector configured to detect said Compton-scattered gamma rays scattered from within said inspected object. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
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27. A measurement system comprising:
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a modulating unit configured to receive source gamma rays or Compton-scattered gamma rays from within an inspected object irradiated by mono-energetic gamma rays from an external gamma radiation source and to modulate gamma fluxes of said source gamma rays or Compton-scattered gamma rays with a periodic function of time; said modulation unit configured to implement an encoding process, wherein said encoding process tags a plurality of solid angle segments of said Compton-scattered or source gamma fluxes individually with different tags; and said modulation unit comprises nodal windows, wherein each nodal window is configured to impose a different time modulation to encode said gamma fluxes, wherein said encoded Compton-scattered or source gamma fluxes are used in combination with a scattering process defined by a Compton energy-angle relationship to determine a three-dimensional distribution of local Compton-scattered gamma fluxes within said inspected object. - View Dependent Claims (28, 29)
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30. A measurement system comprising:
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a measuring device configured to apply a Compton scattering process to an analysis of gamma rays scattered from an inspected object, wherein the gamma rays are irradiated from an external gamma radiation source; wherein scattering points or a plurality of voxels of said Compton-scattered gamma rays having identical energies form an isogonic surface; and a modulating unit comprising nodal windows, wherein each nodal window imposes a different time modulation for encoding a two-dimensional cross-section of source gamma fluxes or Compton-scattered gamma fluxes. - View Dependent Claims (31, 32, 33)
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34. A three-dimensional density image generating system comprising:
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a modulating unit comprising nodal windows; said modulating unit configured to receive source gamma rays or Compton-scattered gamma rays from within an inspected object irradiated by gamma rays from an external gamma radiation source, such that each nodal window imposes a different time modulation to modulate gamma fluxes of said source gamma rays or Compton-scattered gamma rays and configured to encode cross-sectional portions of source gamma fluxes or Compton single-scattered gamma fluxes to locate a first coordinate and a second coordinate of scattering points or voxels within said inspected object; a measuring device configured to identify and separate said source gamma fluxes or said Compton single-scattered gamma fluxes originating from a plurality of voxels present in isogonic slices within the inspected object, and configured to provide a determination of a third coordinate of the scattering points within the inspected object; wherein said measuring device is configured to determine a spatial distribution of said Compton single-scattered gamma fluxes; and wherein said Compton single-scattered gamma flux determination includes a multitude of gamma fluxes of said gamma rays arriving from isogonic slices internal to said inspected object, wherein the isogonic slices comprise portions of isogonic shells within said inspected object.
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35. A non-invasive three-dimensional density distribution measuring device comprising:
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an external isotopic source configured to irradiate an inspected object with gamma rays to generate Compton single-scattered gamma photons, wherein said Compton single-scattered gamma photons obey principles of Compton scattering law; a modulator comprising nodal windows, wherein each nodal window imposes a different time modulation to encode a periodic time-dependent oscillation distributed over a two-dimensional area of a source gamma flux or a Compton single-scattered gamma flux, whereas the source gamma flux comprises a plurality of source gamma photons and the Compton single-scattered gamma flux comprises a plurality of said Compton single-scattered gamma photons; a spectrometer configured to detect energies and intensities of said Compton single-scattered gamma photons; and a multi-channel pulse-height analyzer configured to sort detected gamma signals according to the energies of the detected gamma photons. - View Dependent Claims (36, 37, 38)
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39. An inspection device comprising:
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an external mono-energetic gamma radiation source configured to irradiate an inspected object with gamma photons; a gamma photon detection unit configured to detect Compton-scattered gamma photons emanating from said inspected object; a modulation unit configured to encode source gammas, or Compton-scattered gammas emanating from the inspected object, enroute toward the gamma photon detection unit; a time-varying modulation unit comprising nodal windows, wherein each nodal window imposes a different time modulation to modulate said source gammas or Compton-scattered gammas with a time-variation character of flux attenuation; a gamma signal sorting unit configured to sort counts of said detected Compton-scattered gamma photons into various energy bins; a signal splitting unit configured to split detector output signals from each of said energy bins into multiple equal components; an electronic function generator unit configured to generate digital signals having time-dependent functions; a multiplication unit configured to multiply said digital signals with said detector output signals to form a combined product-function signal; an integration unit configured to integrate, over time, said combined product-function signal to yield a plurality of linear algebraic equations; an equation-solving unit configured to solve said plurality of linear algebraic equations to produce a determination of local Compton-scattered gamma fluxes at points of interest inside the inspected object; and a data processing unit configured to perform said determination of said local Compton-scattered gamma fluxes and reconstruct an image of a three-dimensional density distribution within said inspected object. - View Dependent Claims (40, 41, 42, 43, 77, 78)
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44. A method of generating a three-dimensional density image, comprising:
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irradiating an object with an external source of gamma photons; observing portions of source gamma fluxes or Compton single-scattered gamma fluxes that pass through corresponding nodal windows in a modulating unit and are encoded by each nodal window imposing a different time modulation on said source gamma fluxes or Compton single-scattered gamma fluxes; modulating each portion of said source gamma fluxes or Compton single-scattered gamma fluxes that pass through a nodal window with a different time-varying attenuation function, to generate a system of linear algebraic equations; solving said system of linear algebraic equations to generate a result; and storing said results on a computer readable medium. - View Dependent Claims (45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62)
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63. A method for imaging comprising the steps of:
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irradiating an inspected object with gamma rays from an external gamma radiation source; applying a Compton scattering process to a plurality of gamma rays scattered from within the inspected object; defining isogonic surfaces and associated isogonic shells as loci of scattering points associated with Compton-scattered gammas scattered through identical scattering angles; using a portion of said isogonic shell within the inspected object to form a locus of said scattering points within the inspected object, from which fluxes of said Compton single-scattered gamma photons having the same energy originate, wherein only the portion of the isogonic shell within the inspected object defines an isogonic slice; detecting said gamma photons; sorting signals from the detected Compton-scattered gamma photons according to a plurality of energies; and storing said signals from the detected Compton-scattered gamma photons according to said plurality of energies on a computer readable medium. - View Dependent Claims (64, 67)
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65. A method for generating a three-dimensional image, the method comprising the steps of:
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detecting source gamma rays from an external gamma radiation source or Compton-scattered gamma rays from within an inspected object irradiated by said source gamma rays after modulating gamma fluxes of said source gamma rays or said Compton-scattered gamma rays by passing through nodal windows in a modulating unit, wherein each nodal window imposes a different time modulation on said gamma fluxes; identifying and separating said Compton-scattered gamma fluxes originating from a plurality of scattering locations from the inspected object; formulating a gamma flux calculation procedure, wherein said gamma flux calculation yields magnitudes of Compton single-scattered gamma fluxes arriving from a plurality of known scattering points or voxels within identified isogonic slices and substantially eliminates or reduces multiple-scattered gamma fluxes arriving from said inspected object and background fluxes; and storing said magnitudes of said Compton single-scattered gamma fluxes on a computer readable medium.
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66. A method of generating a flux distribution image, comprising the steps of:
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irradiating an object with gamma rays from an external gamma source to generate Compton single-scattered gamma rays, wherein said Compton single-scattered gamma rays obey principles of Compton scattering law; encoding source gamma flux or Compton single-scattered gamma flux; determining energies and intensity levels of said flux of Compton single-scattered gamma rays; and sorting said energies and measuring flux intensities of portions of the Compton single-scattered gamma flux that pass through nodal windows of a modulator, wherein each nodal window imposes a different time modulation to produce a three-dimensional representation of the local Compton single-scattered gamma flux distribution.
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68. A method of inspecting comprising the steps of:
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irradiating an object with gamma rays from an external gamma source; encoding source gamma fluxes or Compton-scattered gamma fluxes by modulating either said source gamma fluxes or said Compton-scattered gamma fluxes with a time variation character, wherein each nodal window of a modulator imposes a different time modulation on said source gamma fluxes or said Compton-scattered gamma fluxes; detecting the Compton single-scattered gamma fluxes of Compton-scattered gamma photons transmitted from said object; generating output voltage pulse height signals from a detector, based upon individual energies of said detected Compton-scattered gamma photons; sorting of registered counts of the detected Compton single-scattered gamma photons into energy bins of a multi-channel analyzer, according to energies of individual detected Compton single-scattered gamma photons; splitting the output voltage pulse height signals from the multi-channel analyzer into a plurality of equal sets; generating electronic digital signal functions; multiplying components of said output voltage pulse height signals from a detector with said digital signal functions to form combined product-function signals; time-integrating said combined product-function signals to generate a value representing a term in a plurality of linear algebraic equations; storing said plurality of linear algebraic equations for local Compton single-scattered gamma fluxes on a computer readable medium; solving said linear algebraic equations for local Compton single-scattered gamma fluxes; and reconstructing a mass density field of said object by converting numerical local Compton single-scattered gamma fluxes into local mass densities. - View Dependent Claims (79)
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69. A modulating unit comprising:
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an encoder configured to encode source gamma fluxes incident on an inspected object or scattered gamma fluxes scattered from an inspected object as gamma rays irradiated from an external source interact with said inspected object, wherein said object scatters the gamma rays; and a spatial origin identifier configured to identify spatial origins of said scattered gamma rays as source gamma rays or Compton-scattered gamma rays pass through a modulating unit comprising a plurality of nodal windows, wherein each nodal window imposes a different time modulation on said source gamma rays or said Compton-scattered gamma rays. - View Dependent Claims (70, 71, 72, 73, 74, 75, 76, 82, 83)
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80. A method of determining density images inside an inspected object, the method comprising the steps of:
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utilizing at least two gamma source energies at the same location, each source energy having a different energy so that a number of gamma source energies is greater than a number of source locations; combining the number of source locations and the number of source energies to generate a total number of source configurations; multiplying the total number of source configurations by a number of detector locations to indicate a number of independent solvable equation systems and to indicate a maximum number of substances with unknown density distributions having solvable solutions; and storing said number of independent solvable equation systems on a computer readable medium. - View Dependent Claims (81)
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Specification