Practical cone beam image reconstruction using local regions-of-interest
First Claim
1. A method of operating a CT imaging apparatus having a cone beam radiation source and a 2D detector arrangement, for reconstructing an image of a 3D region of interest (ROI) of an object, comprising the following steps:
- operating the source and detector arrangement at a plurality of source positions along a scan path that encircles the region of interest in the object, so as to acquire a set of measurement data at each of the source positions that is representative of radiation attenuation caused by the object as the radiation source and the detector arrangement are operated along the scan path;
conversion processing the acquired measurement data to develop multiple sub-sets of Radon data, each of the sub-sets being targeted for reconstructing a corresponding local 2D ROI in a 2D parallel projection of the object; and
Radon inversion processing of multiple ones of the sub-sets that are grouped together, to develop an image reconstruction of a part of the 3D ROI in the object.
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Abstract
A method and apparatus of operating a CT imaging apparatus having a cone beam radiation source and a 2D detector arrangement, for exactly reconstructing an image of a 3D region of interest (ROI) in an object. Measurement data acquired by the 2D detector is processed to develop sub-sets of Radon data. Each of the sub-sets of Radon data is targeted for reconstructing a corresponding local 2D ROI in a 2D parallel projection of the object. Accordingly, after a sub-set of Radon data is completely developed, it is subjected to a first inversion processing step for developing the corresponding local 2D ROI. Multiple ones of the local ROIs are then grouped together and subjected to a second inversion processing step to develop an image reconstruction of a part of the 3D ROI in the object.
49 Citations
27 Claims
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1. A method of operating a CT imaging apparatus having a cone beam radiation source and a 2D detector arrangement, for reconstructing an image of a 3D region of interest (ROI) of an object, comprising the following steps:
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operating the source and detector arrangement at a plurality of source positions along a scan path that encircles the region of interest in the object, so as to acquire a set of measurement data at each of the source positions that is representative of radiation attenuation caused by the object as the radiation source and the detector arrangement are operated along the scan path; conversion processing the acquired measurement data to develop multiple sub-sets of Radon data, each of the sub-sets being targeted for reconstructing a corresponding local 2D ROI in a 2D parallel projection of the object; and Radon inversion processing of multiple ones of the sub-sets that are grouped together, to develop an image reconstruction of a part of the 3D ROI in the object. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A scanning and data acquisition apparatus for three dimensional (3D) computerized tomography (CT) imaging of a region of interest (ROI) in an object, comprising:
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an energy source for emitting energy in the form of a cone beam; an area detector for detecting as measurement data cone beam energy after attenuation by passage through an object to be imaged; a manipulator for movably positioning said source and detector along a scan path relative to the object, to cause irradiation of said object by said source at multiple source positions along said scan path about said object, said detector acquiring a corresponding set of measurement data at each said source position; control means for defining the scan path as a plurality of positions on a predetermined geometric surface surrounding the object, with each of a plurality of planes that pass through the object and intersect the scan path in at least one point as well as the area detector, being useful for calculating Radon data at a given one of a plurality of Radon samples; image reconstruction processing means including means for calculating Radon data for each of said Radon samples by processing multiple ones of the sets of measurement data, for developing image data; and display means responsive to said image data for displaying a reconstructed image of the object; wherein said image reconstruction processing means comprises; a conversion processor for processing the acquired measurement data to develop multiple sub-sets of Radon data, each of the sub-sets targeted for reconstructing a corresponding local 2D ROI in a 2D parallel projection of the object, and a Radon inversion processor for processing multiple ones of the sub-sets that are grouped together, to develop an image reconstruction of a part of the ROI in the object. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
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Specification