Volumetric computed tomography system for cardiac imaging
First Claim
1. A method for generating an image of an object using a computed tomography (CT) imaging system, the imaging system including an x-ray detector array and a rotating x-ray source projecting an x-ray beam, said method comprising:
- identifying a physiological cycle of the object, the cycle comprising a plurality of phases;
selecting at least one phase of the object;
collecting at least one segment of projection data for each selected phase of the object during each rotation of the x-ray source;
generating a projection data set by combining the projection data segments from more than one cycle of the object; and
generating a cross-sectional image of the entire object from the projection data set.
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Accused Products
Abstract
The present invention, in one form is an imaging system for generating images of an entire object. In one embodiment, a physiological cycle unit is used to determine the cycle of the moving object. By altering the rotational speed of an x-ray source as a function of the object cycle, segments of projection data are collected for each selected phase of the object during each rotation. After completing a plurality of rotations, the segments of projection data are combined and a cross-sectional image of the selected phase of the object is generated. As a result, minimizing motion artifacts.
98 Citations
29 Claims
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1. A method for generating an image of an object using a computed tomography (CT) imaging system, the imaging system including an x-ray detector array and a rotating x-ray source projecting an x-ray beam, said method comprising:
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identifying a physiological cycle of the object, the cycle comprising a plurality of phases;
selecting at least one phase of the object;
collecting at least one segment of projection data for each selected phase of the object during each rotation of the x-ray source;
generating a projection data set by combining the projection data segments from more than one cycle of the object; and
generating a cross-sectional image of the entire object from the projection data set. - View Dependent Claims (2, 3, 4, 11, 12, 13, 14, 15)
rotating the x-ray source a plurality of rotations; and
emitting an x-ray beam from the x-ray source towards the x-ray detector array from a plurality of projection angles.
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4. A method in accordance with claim 3 wherein collecting at least one segment of projection data for each selected phase of the object during each rotation of the x-ray source further comprises collecting each segment of projection data for the selected phase from a different projection angle.
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11. A method in accordance with claim 1 wherein selecting at least one phase of the object comprises:
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selecting a first selected phase of the object; and
selecting a second selected phase of the object.
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12. A method in accordance with claim 1 wherein identifying a physiological cycle of the object comprises identifying a physiological cycle of a heart including a systolic phase and a diastolic phase.
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13. A method in accordance with claim 1 wherein identifying a physiological cycle of the object comprises identifying a physiological cycle of a respiratory system.
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14. A method in accordance with claim 1 wherein generating a projection data set by combining the projection data segments comprises:
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rotating the x-ray source a plurality of projection angles;
collecting projection data for a plurality of projection angles using the detector array; and
rebinning the projection data for each selected phase of the object.
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15. A method in accordance with claim 1 wherein collecting at least one segment of projection data for each selected phase of the object during each rotation of the x-ray source comprises:
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detecting an arrhythmic cycle of the object; and
collecting replacement projection data for the projection data collected during the arrhythmic cycle.
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5. A method for generating an image of an object using a computed tomography (CT) imaging system, the imaging system including an x-ray detector array and a rotating x-ray source projecting an x-ray beam, said method comprising:
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identifying a physiological cycle of the object, the cycle comprising a plurality of phases;
selecting at least one phase of the object;
collecting at least one segment of projection data for each selected phase of the object during each rotation of the x-ray source;
generating a projection data set by combining the projection data segments; and
generating a cross-sectional image of the entire object from the projection data set;
wherein collecting at least one segment of projection data for each selected phase of the object during each rotation of the x-ray source further comprises collecting each set of projection data for the selected phase from a different projection angle;
and further wherein collecting each set of projection data for the selected phase from a different projection angle comprises altering a rotation speed of the x-ray source. - View Dependent Claims (6)
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7. A method for generating an image of an object using a computed tomography (CT) imaging system, the imaging system including an x-ray detector array and at least one rotating x-ray source projecting an x-ray beam, said method comprising:
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identifying a physiological cycle of the object, the cycle comprising a plurality of phases;
selecting at least one phase of the object;
collecting at least one segment of projection data for each selected phase of the object during each rotation of the x-ray source;
generating a projection data set by combining the projection data segments; and
generating a cross-sectional image of the entire object from the projection data set;
wherein collecting at least one segment of projection data for each selected phase of the object during each rotation of the x-ray source further comprises collecting each set of projection data for the selected phase from a different projection angle;
wherein collecting each set of projection data for the selected phase from a different projection angle comprises altering a rotation speed of the x-ray source;
wherein emitting an x-ray beam from the x-ray source towards an x-ray detector from a plurality of projection angles comprises emitting an x-ray beam from the x-ray source for a determined imaging temporal period; and
wherein the rotational speed of each x-ray source is determined in accordance with;
where; Tc is the cardiac cycle time in seconds;
n is an integer constant; and
Rt is the determined imaging temporal period in seconds.
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8. A method for generating an image of an object using a computed tomography (CT) imaging system, the imaging system including an x-ray detector array and at least one rotating x-ray source projecting an x-ray beam, said method comprising:
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identifying a physiological cycle of the object, the cycle comprising a plurality of phases;
selecting at least one phase of the object, collecting at least one segment of projection data for each selected phase of the object during each rotation of the x-ray source;
generating a projection data set by combining the projection data segments; and
generating a cross-sectional image of the entire object from the projection data set;
wherein collecting at least one segment of projection data for each selected phase of the object during each rotation of the x-ray source further comprises collecting each set of projection data for the selected phase from a different projection angle;
wherein collecting each set of projection data for the selected phase from a different projection angle comprises altering a rotation speed of the x-ray source;
wherein emitting an x-ray beam from the x-ray source towards an x-ray detector from a plurality of projection angles comprises emitting an x-ray beam from the x-ray source for a determined imaging temporal period; and
wherein collecting at least one segment of projection data for each cycle of the object comprises altering the rotational speed of the x-ray source in accordance with;
where; w is a period of a physiological cycle (in seconds), γ
is a projection angle range for a complete projection data set (in degrees), andn is a selected integer number of cycles to collect a complete projection data set.
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9. A method for generating an image of an object using a computed tomography (CT) imaging system, the imaging system including an x-ray detector array and at least one rotating x-ray source projecting an x-ray beam, said method comprising:
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identifying a physiological cycle of the object, the cycle comprising a plurality of phases;
selecting at least one phase of the object;
collecting at least one segment of projection data for each selected phase of the object during each rotation of the x-ray source;
generating a projection data set by combining the projection data segments; and
generating a cross-sectional image of the entire object from the projection data set;
wherein collecting at least one segment of projection data for each selected phase of the object during each rotation of the x-ray source further comprises collecting each set of projection data for the selected phase from a different projection angle;
wherein collecting each set of projection data for the selected phase from a different projection angle comprises altering a rotation speed of the x-ray source;
wherein emitting an x-ray beam from the x-ray source towards an x-ray detector from a plurality of projection angles comprises emitting an x-ray beam from the x-ray source for a determined imaging temporal period; and
wherein collecting at least one segment of projection data for each cycle of the object comprises altering the rotational speed of the x-ray source in accordance with;
where; w is a period of a physiological cycle (in seconds), γ
is a projection angle range for a complete projection data set (in degrees), andn is a selected number of cycles to collect a complete projection data set.
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10. A computed tomography (CT) imaging system for generating an image of an object, said imaging system including an x-ray detector array and a rotating x-ray source projecting an x-ray beam, said imaging system configured to:
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identify a physiological cycle of the object, the cycle comprising a plurality of phases;
accept an input from an operator specifying at least one phase of the object;
collect at least one segment of projection data for each selected phase of the object during each rotation of the x-ray source;
generate a projection data set by combining the projection data segments; and
generate a cross-sectional image of the entire object from said projection data set;
wherein to collect at least one segment of projection data for each cycle of the object, said imaging system configured to alter the rotational speed of said x-ray source in accordance with;
where; w is a period of a physiological cycle (in seconds), γ
is a projection angle range for a complete projection data set (in degrees), andn is a selected integer number of cycles to collect a complete projection data set.
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16. A computed tomography (CT) imaging system for generating an imaging of an object, said imaging system including an x-ray detector array and a rotating x-ray source projecting an x-ray beam, said imaging system configured to:
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identify a physiological cycle of the object, the cycle comprising a plurality of phases;
accept an input from an operator specifying at least one phase of the object;
collect at least one segment of projection data for each selected phase of the object during each rotation of the x-ray source;
generate a projection data set by combining said projection data segments from more than one cycle of the object; and
generate a cross-sectional image of the entire object from said projection data set. - View Dependent Claims (17, 18, 19, 24, 25, 26, 27, 28, 29)
rotate said x-ray a plurality of rotations; and
emit an x-ray beam from said x-ray source toward said x-ray detector array from a plurality of projection angles.
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19. An imaging system in accordance with claim 18 wherein to collect at least one segment of projection data from each selected phase of the object during each rotation of said x-ray source, said imaging system further configured to collect each segment of projection data for the selected phase from a different projection angle.
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24. An imaging system in accordance with claim 16 wherein said rotating x-ray source is a first rotating x-ray source, said x-ray detector array is a first x-ray detector array, and further comprising a second rotating x-ray source and a second detector array, and wherein to collect at least one segment of projection data, said imaging system is configured to collect at least one segment of projection data for each selected phase of the object during each rotation of the first x-ray source.
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25. An imaging system in accordance with claim 16 wherein to accept an input from an operator specifying at least one phase of the object, said imaging system configured to:
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accept an input from an operator to select a first selected phase of the object; and
accept an input from an operator to select a second selected phase of the object.
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26. An imaging system in accordance with claim 16 wherein to identify a physiological cycle of the object, said imaging system configured to identify a physiological cycle of a heart comprising a systolic phase and a diastolic phase.
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27. An imaging system in accordance with claim 16 wherein to identify a physiological cycle of the object, said imaging system configured to identify a physiological cycle of a respiratory system.
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28. An imaging system in accordance with claim 16 wherein to generate a projection data set by combining the projection data segments, said imaging system configured to:
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rotate said x-ray source a plurality of projection angles;
collect projection data for a plurality of projection angles using said detector array; and
rebin the projection data for each selected phase of the object.
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29. An imaging system in accordance with claim 16 wherein to collect at least one segment of projection data for each selected phase of the object during each rotation of said x-ray source, said imaging system configured to:
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detect an arrhythmic cycle of the object; and
collect replacement projection data for the projection data collected during said arrhythmic cycle.
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20. A computed tomography (CT) imaging system for generating an image of an object, said imaging system including an x-ray detector array and a rotating x-ray source projecting an x-ray beam, said imaging system configured to:
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identify a physiological cycle of the object, the cycle comprising a plurality of phases;
accept an input from an operator specifying at least one phase of the object;
collect at least one segment of projection data for each selected phase of the object during each rotation of the x-ray source;
generate a projection data set by combining the projection data segments; and
generate a cross-sectional image of the entire object from said projection data set;
wherein to collect at least one segment of projection data for each selected phase of the object during each rotation of said x-ray source, said system is configured to alter a rotational speed of the x-ray source. - View Dependent Claims (21)
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22. A computed tomography (CT) imaging system for generating an image of an object, said imaging system including an x-ray detector array and a rotating x-ray source projecting an x-ray beam, said imaging system configured to:
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identify a physiological cycle of the object, the cycle comprising a plurality of phases;
accept an input from an operator specifying at least one phase of the object;
collect at least one segment of projection data for each selected phase of the object during each rotation of the x-ray source;
generate a projection data set by combining the projection data segments; and
generate a cross-sectional image of the entire object from said projection data set;
wherein the rotational speed of said x-ray source is determined in accordance with;
where; Tc is the cardiac cycle time in seconds;
n is an integer constant; and
Rt is said determined imaging temporal period in seconds.
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23. A computed tomography (CT) imaging system for generating an image of an object, said imaging system including an x-ray detector array and a rotating x-ray source projecting an x-ray beam, said imaging system configured to:
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identify a physiological cycle of the object, the cycle comprising a plurality of phases;
accept an input from an operator specifying at least one phase of the object;
collect at least one segment of projection data for each selected phase of the object during each rotation of the x-ray source;
generate a projection data set by combining the projection data segments; and
generate a cross-sectional image of the entire object from said projection data set;
wherein to collect at least one segment of projection data for each cycle of the object, said imaging system configured to alter the rotational speed of said x-ray source in accordance with;
where; w is a period of a physiological cycle (in seconds), γ
is a projection angle range for a complete projection data set (in degrees), andn is a selected number of cycles to collect a complete projection data set.
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Specification