Computed tomography scanner with large gantry bore
First Claim
1. A computed tomography imaging system including:
- a rotating gantry that rotates about an examination region along a longitudinal axis;
a first radiation source disposed on the rotating gantry and arranged to emit first radiation into the examination region;
a second radiation source disposed on the rotating gantry and arranged to emit second radiation into the examination region, the second radiation source being angularly spaced around the gantry from the first radiation source;
a first asymmetrically adjustable collimator that is asymmetrically adjustable in a direction generally perpendicular to the longitudinal axis to position a first outer x-ray projection of the first radiation relative to a second outer x-ray projection of the first radiation;
a second asymmetrically adjustable collimator that is asymmetrically adjustable in a direction generally perpendicular to the longitudinal axis to position a first outer x-ray projection of the second radiation relative to a second outer x-ray projection of the second radiation;
a first radiation detector arranged to receive the first radiation, a center of the first radiation detector being angularly spaced around the gantry from the first radiation source by less than 180°
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a second radiation detector arranged to receive the second radiation, a center of the second radiation detector being angularly spaced around the gantry from the second radiation source by less than 180°
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a reconstruction processor that reconstructs projection data acquired during gantry rotation by the first and second radiation detectors into one or more image representations;
wherein the first asymmetrically adjustable collimator has a fixed collimation edge that defines the second outer x-ray projection of the first radiation and an adjustable collimation edge that defines the first outer x-ray projection of the first radiation,the second asymmetrically adjustable collimator has a fixed collimation edge that defines the second outer x-ray projection of the second radiation and an adjustable collimation edge that defines the first outer x-ray projection of the second radiation, andeach of the adjustable collimation edges moves between a first position at which the first and second radiation is symmetrical about the rotational center and at least one other position at which the first and second radiation is asymmetrical about the rotational center.
1 Assignment
0 Petitions
Accused Products
Abstract
A computed tomography scanner includes a rotating gantry (20) defining an examination region (16). A first radiation source (22) is disposed on the rotating gantry (20) and emits first radiation (32) into the examination region (16). A second radiation source (24) is disposed on the rotating gantry (20) and emits second radiation (36) into the examination region (16). The second radiation source (24) is angularly spaced around the gantry from the first radiation source (22). A first radiation detector (30, 30′) receives the first radiation (32). A center of the first radiation detector (30, 30′) is angularly spaced around the gantry from the first radiation source (22) by less than 180°. A second radiation detector (34) receives the second radiation (36). A center of the second radiation detector (34) is angularly spaced around the gantry from the second radiation source (24) by less than 180°.
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Citations
26 Claims
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1. A computed tomography imaging system including:
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a rotating gantry that rotates about an examination region along a longitudinal axis; a first radiation source disposed on the rotating gantry and arranged to emit first radiation into the examination region; a second radiation source disposed on the rotating gantry and arranged to emit second radiation into the examination region, the second radiation source being angularly spaced around the gantry from the first radiation source; a first asymmetrically adjustable collimator that is asymmetrically adjustable in a direction generally perpendicular to the longitudinal axis to position a first outer x-ray projection of the first radiation relative to a second outer x-ray projection of the first radiation; a second asymmetrically adjustable collimator that is asymmetrically adjustable in a direction generally perpendicular to the longitudinal axis to position a first outer x-ray projection of the second radiation relative to a second outer x-ray projection of the second radiation; a first radiation detector arranged to receive the first radiation, a center of the first radiation detector being angularly spaced around the gantry from the first radiation source by less than 180°
;a second radiation detector arranged to receive the second radiation, a center of the second radiation detector being angularly spaced around the gantry from the second radiation source by less than 180°
; anda reconstruction processor that reconstructs projection data acquired during gantry rotation by the first and second radiation detectors into one or more image representations; wherein the first asymmetrically adjustable collimator has a fixed collimation edge that defines the second outer x-ray projection of the first radiation and an adjustable collimation edge that defines the first outer x-ray projection of the first radiation, the second asymmetrically adjustable collimator has a fixed collimation edge that defines the second outer x-ray projection of the second radiation and an adjustable collimation edge that defines the first outer x-ray projection of the second radiation, and each of the adjustable collimation edges moves between a first position at which the first and second radiation is symmetrical about the rotational center and at least one other position at which the first and second radiation is asymmetrical about the rotational center. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A computed tomography imaging system including:
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a rotating gantry defining an examination region, the examination region including a central region that contains a center of rotation of the rotating gantry and a surrounding region that surrounds the central region, the rotating gantry further defining a gantry plane of gantry rotation and an axial direction; a first radiation source disposed on the rotating gantry, the first radiation source producing first radiation directed into the examination region; a first radiation detector array arranged to receive the first radiation after the first radiation passes through the examination region, the first detector array including; a high resolution portion with detector elements of a first size that receive first radiation that passes through the central region, and a low resolution portion with detector elements of a second size that receive first radiation that passes through the surrounding region but not the central region, wherein the second size is larger than the first size; a second radiation source disposed on the rotating gantry, the second radiation source being positioned at an angular offset on the rotating gantry relative to the first radiation source, the second radiation source producing second radiation directed into the examination region; a second radiation detector array arranged to receive the second radiation after the second radiation passes through the examination region, the second detector array including; a high resolution portion with detector elements of a third size that receive second radiation that passes through the central region, and a low resolution portion with detector elements of a fourth size that receive second radiation that passes through the surrounding region but not the central region, wherein the fourth size is larger than the third size, wherein the high resolution portions of the first and second radiation detector arrays are arranged on the rotating gantry between the low resolution portions of the first and second radiation detector arrays; wherein the first and second radiation detector arrays together define a single unitary radiation detector array, the single unitary radiation detector array including; a central high resolution portion defined b the high resolution portions of the first and second radiation detector arrays; a first outer low resolution portion defined by the low resolution portion of the first radiation detector array; and a second outer low resolution portion defined b the low resolution portion of the second radiation detector array, wherein the central high resolution portion is arranged between the first and second outer low resolution portions; and a reconstruction processor that reconstructs projection data acquired during gantry rotation by the first and second radiation detector arrays into an image representation. - View Dependent Claims (19, 20, 21, 22, 23)
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24. A computed tomography imaging method including:
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passing first radiation through an examination region, the examination region including a central region and a surrounding region; measuring central projections, corresponding to rays of first radiation that intersect the central region, using a first high-resolution detector array that has a first spacing of detector elements; measuring surrounding projections, corresponding to rays of first radiation that intersect the surrounding region without intersecting the central region, using a first low-resolution detector array that has a second spacing of detector elements, the second spacing being larger than the first spacing; passing second radiation through the examination region; measuring central projections, corresponding to rays of second radiation that intersect the central region, using a second high-resolution detector array that has the first spacing of detector elements; measuring surrounding projections, corresponding to rays of second radiation that intersect the surrounding region without intersecting the central region, using a second low-resolution detector array that has the second spacing of detector elements; and reconstructing the central projections and the surrounding projections corresponding to the first radiation and the second radiation to generate a reconstructed image representation, wherein the reconstructing includes; combining 90°
contiguous angular segments of the central projections corresponding to the first radiation and the second radiation during reconstructing of voxels within the central region; andcombining 180°
contiguous angular segments of the central and surrounding projections corresponding to the first radiation and the second radiation during reconstructing of voxels in the surrounding region outside a transition radius. - View Dependent Claims (25, 26)
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Specification