Method and apparatus for computerized tomographic scanning with plural intersecting sets of parallel radiation beams
First Claim
1. A tomographic scanner for scanning an area of interest, said tomographic scanner comprising:
- (a) a source of penetrating radiation;
(b) first means for moving said source of penetrating radiation in a first arc which is subtended by an angle of at least approximately 120°
centered on said source in the area of interest,(c) a detector array comprising an endless chain of detectors; and
(d) second means for moving said detector array in a second arc which is subtended by an angle of at least approximately 120°
centered on said source;
(e) said first and second arcs being sized and shaped and said first and second means being adapted to cause said source and said detector array to move at velocities such that a plurality of parallel beam paths may be propagated from said source through said area to said detector array in each of a plurality of angular positions of said source and said detector array.
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Accused Products
Abstract
An array of radiation detectors is rotated about one or more sources of fan-shaped substantially planar radiation beams which are, in turn, rotated in the opposite direction about a three-dimensional body such that substantially parallel paths are defined between given individual detectors of the array and the radiation sources during the course of their oppositely directed movements. Radiation absorption measurements are taken along thusly defined plural intersecting sets of substantially parallel paths within a desired cross-section of the three-dimensional body to provide data for use in computing and displaying a constructed visual image of structures having different radiation absorption coefficients within the cross-section.
22 Citations
84 Claims
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1. A tomographic scanner for scanning an area of interest, said tomographic scanner comprising:
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(a) a source of penetrating radiation; (b) first means for moving said source of penetrating radiation in a first arc which is subtended by an angle of at least approximately 120°
centered on said source in the area of interest,(c) a detector array comprising an endless chain of detectors; and (d) second means for moving said detector array in a second arc which is subtended by an angle of at least approximately 120°
centered on said source;(e) said first and second arcs being sized and shaped and said first and second means being adapted to cause said source and said detector array to move at velocities such that a plurality of parallel beam paths may be propagated from said source through said area to said detector array in each of a plurality of angular positions of said source and said detector array.
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2. A tomographic scanner for scanning an area of interest comprising a penetrating radiation source moving in an arc encompassing said area of interest and a detector array comprising an endless chain of detectors moving in an arc encompassing said area of interest and circumscribing said source, said detector array moving in a direction opposite to the direction of said source so that a plurality of parallel beam paths are propagated from said source to said detector array over a plurality of angular positions through said area.
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3. A tomographic scanner providing radiation beam absorption measurements taken along plural intersecting sets of substantially parallel paths within a cross-section of a three-dimensional body, said tomographic scanner comprising:
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a plurality of radiation sources disposed to direct respective fan-shaped beams of radiation through a desired cross-section of a three-dimensional body, said radiation sources being mounted for rotation in a first direction at least part-way around said three-dimensional body, and an array of radiation detectors disposed opposite said radiation sources for intercepting said fan-shaped beam of radiation after it has been partially absorbed by said said array of radiation detectors being mounted for rotation in a second direction opposite said first direction at least part-way around said three-dimensional body such that substantially parallel paths are defined between given individual detectors of the array and a given radiation source during the course of their oppositely directed movements, said plurality of radiation sources being spaced apart round the three-dimensional body and said array of radiation detectors substantially circumscribing said three-dimensional body such that a different segment of the array is disposed opposite each radiation source during each phase of said rotations; wherein said array of radiation detectors comprises an endless chain of individual detectors mounted for movement in a path circumscribing said plurality of radiation sources. - View Dependent Claims (4)
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5. A method of tomographic scanning comprising:
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operating radiation sources to generate three fan-shaped beams of radiation each directed inwardly toward a desired cross-section of a three-dimensional body form spaced locations thereabout, rotating said three fan-shaped beams in a first direction and in unison at least part-way around said three-dimensional body, scanning different portions of the fan-shaped beams after passage through said three-dimensional body with a plurality of spaced-apart radiation detectors rotating in unison at least part-way around said three-dimensional body in a second direction generally opposite said first direction such that plural intersection sets of parallel paths are spaced locations, and measuring the radiation absorption experienced along said plural intersecting sets of parallel paths so as to provide data for use in constructing a visual depiction of said desired cross-section; wherein said scanning step is performed along arcs disposed at substantially equal and constant distances from said radiation sources over respectively corresponding portions of the path of detector movement. - View Dependent Claims (6)
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7. A tomographic scanner providing radiation beam absorption measurements taken along plural intersecting sets of substantially parallel paths within a cross-section of three-dimensional body, said tomographic scanner comprising:
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a plurality of radiation sources disposed to direct respective fan-shaped beams of radiation through a desired cross-section of a three-dimensional body, said radiation sources being mounted for rotation in a first direction at least part-way around said three-dimensional body, and an array of radiation detectors disposed opposite said radiation sources for intercepting said fan-shaped beam of radiation after it has been partially absorbed by said three-dimensional body, said array of radiation detectors being mounted for rotation in a second direction opposite said first direction at least part-way around said three-dimensional body such that substantially parallel paths are defined between give individual detectors of the array and a given radiation source during the course of their oppositely directed movement, said plurality of radiation sources being spaced apart around the three-dimensional body and said array of radiation detectors substantially circumscribing said three-dimensional body such that a different segment of the array is disposed opposite each radiation source during each phase of said rotations; wherein said array of radiation detectors is mounted or movement along a corresponding plurality of circular arcs, each arc being centered on its respectively associated radiation source. - View Dependent Claims (8, 9)
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10. A tomographic scanner providing radiation beam absorption measurements taken along plural intersecting sets of substantially parallel paths within a cross-section of a three-dimensional body, said tomographic scanner comprising:
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a plurality of radiation sources disposed to direct respective fan-shaped beams of radiation through a desired cross-section of a three-dimensional body, said radiation sources being mounted for rotation in a first direction at least part-way around said three-dimensional body, and said array of radiation detectors disposed opposite said radiation sources for intercepting said fan-shaped beam of radiation after it has been partially absorbed by said three-dimensional body, said array of radiation detectors being mounted for rotation in a second direction opposite said first direction at least part-way around said three-dimensional body such that substantially parallel paths are defined between given individual detectors of the array and a given radiation source during the course of their oppositely directed movements, said plurality of radiation sources being spaced apart around the three-dimensional body and said array of radiation detectors substantially circumscribing said three-dimensional body such that a different segment of the array is disposed opposite each radiation source during each phase of said rotations; wherein said array of radiation detectors is mounted for movement of each individual detector at a substantially constant distance from the radiation source then illuminating such individual detector during the course of their oppositely directed movements.
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11. A tomographic scanner providing radiation beam absorption measurements taken along plural intersecting sets of substantially parallel paths within a cross-section of a three-dimensional body, said tomographic scanner comprising:
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a radiation source disposed to direct a fan-shaped beam of radiation through a desired cross-section of a three-dimensional body, said radiation source being mounted for continuous rotation in a first direction around a substantial portion of said three-dimensional body, and an array of radiation detectors disposed opposite said radiation source for intercepting said fan-shaped beam of radiation after it has been partially absorbed by said three-dimensional body, said array of radiation detectors being mounted for continuous rotation in a second direction opposite said first direction around a substantial portion of said three-dimensional body, each individual detector being moved relative to said source across different portions of said fan-shaped beam such that substantially parallel paths are defined between give individual detectors of the array and the radiation source during the course of their oppositely directed movements; wherein said array of radiation detectors is mounted for movement at a substantially constant distance from said radiation source over at least a portion of the path of movement.
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12. A tomographic scanner comprising:
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an aperture for accepting a three-dimensional body thereinto; three radiation sources equally spaced apart about the circumference of a circle centered on said aperture, each radiation source being disposed to direct a fan-shaped substantially planar beam of radiation through a cross-section of said three-dimensional body and between the remaining two of said radiation sources; said three radiation sources being fixedly mounted with respect to each other and mounted for rotation in unison in a first direction about an axis substantially perpendicular to the plane of said fan-shaped radiation beams; an endless array of radiation detectors disposed on three intersecting paths, each path being situated between a pair of said radiation sources such that the detectors disposed on a path between two radiation sources intercept the fan-shaped radiation beam from the remaining third radiation source; said endless array of radiation detectors being mounted for movement along said paths in a second direction opposite said first direction; and driving members coupled to said radiation sources and to said array of radiation detectors for driving them through their oppositely directed movements so as to define plural intersecting sets of substantially parallel paths between said radiation sources and the individual radiation detectors in said array. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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23. A method of tomographic scanning comprising:
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rotating at least one substantially planar beam of radiation continuously in a first direction with respect to a three-dimensional body, and scanning the planar beam of radiation after passage through said three-dimensional body with a plurality of radiation detectors rotating continuously in a second direction generally opposite said first direction, each individual detector being moved relative to said beam across different portions of said planar beam so as to define plural intersecting sets of parallel paths, each set respectively corresponding to one of said detectors, along which parallel paths radiation absorption measurements may be taken; wherein said scanning step comprises continuous movement along a portion of an arc situated at a constant distance from a source of said at least one substantially planar radiation beam. - View Dependent Claims (24)
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25. A tomographic scanner providing radiation beam absorption measurements along plural substantially parallel paths within a cross-section of a three-dimensional body, said tomographic scanner comprising:
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a plurality of radiation sources disposed to direct respective fan-shaped beams of radiation through a cross-section of a three-dimensional body; said radiation sources being mounted for rotation in a first direction at least part-way around said three-dimensional body; and a plurality of radiation detectors disposed opposite said radiation sources for intercepting said fan-shaped beams of radiation after being partially absorbed by said three-dimensional body; said radiation detectors being mounted for rotation in a second direction opposite said first direction at least part-way around said three-dimensional body such that the detectors successively scan different portions of the fan-shaped beams and define substantially parallel paths along which respectively corresponding successive radiation absorption measurements are thereby provided during the course of the oppositely directed movements of the radiation sources and radiation detectors, said plurality of radiation sources being spaced apart and around an aperture disposed to receive the three-dimensional body and being mounted for movement in unison thereabout; and said plurality of radiation detectors being mounted for movement in unison so as to substantially simultaneously define plural intersecting sets of substantially parallel paths within said cross-section; said tomographic scanner further comprising means confining the movement of said radiation detectors to arcs of substantially constant and equal distances from opposingly disposed radiation sources over respectively corresponding portions of the path of movement. - View Dependent Claims (26, 27, 28, 29, 30, 31, 33, 35, 39)
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32. A tomographic scanner providing radiation beam absorption measurements along plural substantially parallel paths within a cross section of a three-dimensional body, said tomographic scanner comprising:
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at least one radiation source disposed to direct a fan-shaped beam of radiation through a cross-section of a three-dimensional body; said at least one radiation source being mounted for continuous rotation in a first direction around a substantial portion of said three-dimensional body; and at least one radiation detector disposed opposite said at least one radiation source for intercepting said fan-shaped beam of radiation after it has been partially absorbed by said three-dimensional body; said at last one radiation detector being mounted for continuous rotation in a second direction opposite said first direction around a substantial portion of said three-dimensional body while moving relative to said at least one source across different portions of said fan-shaped beam such that said at least one radiation detector successively scans different portions of the fan-shaped beam and defines substantially parallel paths along which respectively corresponding successive radiation absorption measurements are thereby provided during the course of the oppositely directed movements of said at least one radiation source and said at least one radiation detector; said tomographic scanner further comprising means confining the movement of said at least one radiation detector to an arc of substantially constant distance from said at least one radiation source over at least a portion of the path of movement. - View Dependent Claims (34, 36)
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37. A tomographic scanner providing radiation beam absorption measurements along plural substantially parallel paths within a cross-section of a three-dimensional body, said tomographic scanner comprising:
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a plurality of radiation sources disposed to direct respective fan-shaped beam as of radiation through a cross-section of a three-dimensional body; said radiation sources being mounted for rotation in a first direction at least part-way around said three-dimensional body; and a plurality of radiation detectors disposed opposite said radiation sources for intercepting said fan-shaped beams of radiation after being partially absorbed by said three-dimensional body; said radiation detectors being mounted for rotation in a second direction opposite said first direction at least part-way around said three-dimensional body such that the detectors successively scan different portion of the fan-shaped beams and defined substantially parallel paths along which respectively corresponding successive radiation absorption measurements are thereby provided during the course of the oppositely directed movements of the radiation sources and radiation detectors, said plurality of radiation sources being spaced apart and around an aperture disposed to receive the three-dimensional body and being mounted for movement in unison thereabout; and said plurality of radiation detectors being mounted for movement in unison so as to substantially simultaneously define plural intersecting sets of substantially parallel paths within said cross-section; wherein said plurality of radiation detectors comprises an endless movable chain of individual inwardly directed detectors circumscribing said plurality of radiation sources. - View Dependent Claims (38, 40, 41, 42)
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43. A method of tomographic scanning a cross-section of a three-dimensional body and measuring radiation beam absorption therewith along a set of parallel paths to provide measurements which may be utilized in constructing a cross-sectional depiction of structures within the three-dimensional body having differing radiation absorption properties, said method comprising the steps of:
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directing a fan-shaped beam of radiation from a radiation source through a desired cross-section of a three-dimensional body, continuously rotating said radiation source with respect to said three-dimensional body in a first direction, scanning different portions of said fan-shaped beam with a radiation detector while rotating the radiation detector with respect to said radiation source in a second direction opposite said first direction such that a set of parallel paths are defined between the radiation detector and the radiation source during their oppositely directed movements, and measuring the radiation absorption encountered along thusly defined parallel paths; wherein said scanning step is performed at a substantially constant distance from said radiation source. - View Dependent Claims (44, 45, 46, 47, 48)
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49. A method of tomographic scanning comprising:
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rotating at least one substantially planar beam of radiation form at least one radiation source continuously in a first direction with respect to a three-dimensional body, and scanning the planar beam of radiation after passage through said three-dimensional body with a plurality of radiation detectors rotating continuously in a second direction generally opposite said first direction, each individual detector being moved relative to said beam across different portions of said planar beam so as to define plural intersecting sets of parallel paths, each set respectively corresponding to one of said detectors, along which parallel paths radiation absorption measurements may be taken; wherein said scanning step comprises continuous movement along the outer portions of intersecting arcs subtending substantially 120 degrees situated at equal constant distances from said at least one radiation source. - View Dependent Claims (50)
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51. Apparatus for providing a plurality of sets of parallel absorption measurements through a body section comprising:
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a radiation source for producing a fan-beam to irradiate said body section; a plurality of radiation detectors, disposed on an arc of predetermined constant radius form said source, for producing indices of the absorption of radiation by said body section along respective paths oriented at respective predetermined angles with respect to said body section; means for moving said source about said body section; and means for translating said detectors in a direction and at a rate to effectively offset any angular deviation of the path between the respective detector means and said source from said respective predetermined angles. - View Dependent Claims (52, 53, 54, 55, 56)
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57. Apparatus for providing a plurality of sets of parallel absorption measurements through a body section comprising:
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three radiation sources for producing respective fan-beams to irradiate said body section, said sources being relatively disposed at 120°
intervals about said body section and adapted for rotation in unison about said body section,a plurality of radiation detectors mutually connected in an endless chain and disposed about said body section outwardly of said sources on plural arcs of predetermined radius from said sources, for producing indices of the absorption of radiation by said body section along respective paths oriented at respective predetermined angles with respect to said body section, means for moving said sources about said body section; and means for translating said detectors in a direction and at a rate to effectively offset any angular deviation of the path between the respective detector means and said source from said respective predetermined angles. - View Dependent Claims (58)
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59. A tomographic scanner comprising:
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at least one radiation source providing a fan-shaped beam of radiation, an array of radiation detectors directed to receive radiation from said source, said radiation source and individual ones of said radiation detectors being mounted for continuous motion along curvilinear loci separated by a constant distance as measured along spaced-apart parallel lines and said individual ones of said radiation detectors being moved across different portions of said fan-shaped beam and constantly directed along successive parallel radiation beam paths at said radiation source during such motion. - View Dependent Claims (60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70)
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71. A method of tomographic scanning comprising:
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directing at least one fan-shaped beam of radiation towards a three-dimensional body under examination, scanning said beam of radiation about said body along a first curvilinear locus, scanning at least one radiation detector through different portions of said beam along a second curvilinear locus constantly spaced from said first locus, as measured along spaced-apart parallel lines, while maintaining a constant orientation of the detector with respect to the source of said radiation beam so as to define plural parallel radiation paths between the source and the detector during said scanning motion. - View Dependent Claims (72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83)
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84. A tomographic scanner providing radiation beam absorption measurements taken along plural intersecting sets of substantially parallel paths within a cross-section of a three-dimensional body, said tomographic scanner comprising:
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a radiation source disposed to direct a a fan-shaped beam of radiation through a desired cross-section of a three-dimensional body, said radiation source being mounted for continuous rotation in a first direction around a substantial portion of said three-dimensional body, and an array of radiation detectors disposed opposite said radiation source for intercepting said fan-shaped beam of radiation after it has been partially absorbed by said three-dimensional body, said array of radiation detectors being mounted for continuous rotation in a second direction opposite said first direction around a substantial portion of said three-dimensional body, each individual detector being moved relative to said source across different portions of said fan-shaped beam such that substantially parallel paths are defined between given individual detectors of the array and the radiation source during the course of their oppositely directed movements; wherein said array of radiation detectors is mounted for movement along a circular arc centered on said radiation source.
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Specification