Exact region of interest cone beam imaging using 3D backprojection
First Claim
1. A method for performing three dimensional computerized tomography imaging of a region-of-interest (ROI) in an object using a cone beam source of radiation energy, comprising the steps of:
- defining a source scanning trajectory as a scan path traversed by the source;
using the cone beam source, fixed relative to an area detector with both source and detector movably positioned relative to the object, to apply radiation energy towards the object from a plurality of source positions along the scan path as said source traverses the scan path, and cause said area detector to acquire cone beam projection data corresponding to respective portions of the object at each of said source positions;
calculating a line integral derivative for each of a plurality of line segments L formed in the cone beam projection data acquired at each of said source positions, the extent of said line segments L in the cone beam data acquired at a given one of said source positions being determined by a mask formed by cone beam projections onto the plane of the detector of portions of the source scan path that are above and below the given one of said source positions;
2D backprojecting the line integral derivatives calculated for a plurality of said line segments L onto a 2D space corresponding to the plane of the detector; and
3D backprojecting the results of the 2D backprojecting step into a 3D space, thereby reconstructing a 3D image of the ROI in the object.
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Accused Products
Abstract
A scanning and data acquisition method and apparatus for three dimensional (3D) computerized tomography (CT) imaging of an object, wherein a plurality of line integral derivatives for a respective plurality of line segments L formed in cone beam projection data acquired on a detector at a plurality of source positions, are calculated. The extent of line segments L in the data acquired at each of the source positions is determined by a mask formed by cone beam projections onto the plane of the detector of portions of the source scan path that are above and below the source position that acquired the cone beam data in which the line integral derivatives for line segments L are being calculated. The line integral derivatives calculated for a plurality of the line segments L are then backprojected onto a 2D space corresponding to the plane of the detector. Finally, the results of the 2D backprojecting step are 3D backprojected into a 3D space, thereby reconstructing a 3D image of the object.
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Citations
24 Claims
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1. A method for performing three dimensional computerized tomography imaging of a region-of-interest (ROI) in an object using a cone beam source of radiation energy, comprising the steps of:
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defining a source scanning trajectory as a scan path traversed by the source; using the cone beam source, fixed relative to an area detector with both source and detector movably positioned relative to the object, to apply radiation energy towards the object from a plurality of source positions along the scan path as said source traverses the scan path, and cause said area detector to acquire cone beam projection data corresponding to respective portions of the object at each of said source positions; calculating a line integral derivative for each of a plurality of line segments L formed in the cone beam projection data acquired at each of said source positions, the extent of said line segments L in the cone beam data acquired at a given one of said source positions being determined by a mask formed by cone beam projections onto the plane of the detector of portions of the source scan path that are above and below the given one of said source positions; 2D backprojecting the line integral derivatives calculated for a plurality of said line segments L onto a 2D space corresponding to the plane of the detector; and 3D backprojecting the results of the 2D backprojecting step into a 3D space, thereby reconstructing a 3D image of the ROI in the object. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. Apparatus for performing three dimensional computerized tomography imaging of a region-of-interest (ROI) in an object using a cone beam source of radiation energy, comprising:
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a source of cone beam radiation energy; a manipulator for providing a source scanning trajectory as a scan path that encircles the ROI in the object and causes the source and detector to traverse the scan path; means for causing the source to apply radiation energy towards the object from a plurality of source positions along the scan path as said source traverses the scan path, said area detector acquiring cone beam projection data corresponding to respective portions of the object at each of said source positions; and an image reconstruction processor for, calculating a line integral derivative for each of a plurality of line segments L formed in the cone beam projection data acquired at each of said source positions, the extent of said line segments L in the cone beam data acquired at a given one of said source positions being determined by a mask calculated by said image reconstruction processor that corresponds to the shape of cone beam projections onto the plane of the detector of portions of the source scan path that are above and below the given one of said source positions, 2D backprojecting the line integral derivatives calculated for a plurality of said line segments L onto a 2D space corresponding to the plane of the detector, and 3D backprojecting the 2D backprojection results into a 3D space, thereby reconstructing a 3D image of the ROI in the object. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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Specification