Abstract: A method, computed tomography (CT) system and computer-readable medium for reconstructing an image volume of an object scanned in helical mode. An embodiment of the method includes determining discrete focal lengths within an imaging plane of the reconstructed field of view comprising the image volume; generating a circular scan sinogram(s) for the discrete focal lengths by interpolating the helical views; selecting within a backprojection operation a circular scan sonogram(s), for one or more image points within the imaging plane, over one or more circular views. The method then includes using the selected circular scan sinogram(s), in the backprojection of the image points point(s) over the circular views view(s) and performing a backprojection for all the image points over all the circular views to generate a reconstructed image of the object.

Abstract: A method for generating an image of an object is provided. The method comprises acquiring projection data at one or more projection views along a circular scan trajectory and generating a corrected projection dataset based upon a weighted derivative applied to a subset of the projection data. The method further comprises backprojecting the corrected projection dataset along one or more projection rays associated with one or more of the projection views, to generate a reconstructed image of the object.

Abstract: A method for analytically reconstructing a multi-axial computed tomography (CT) dataset, acquired using one or more longitudinally-offset x-ray beams emitted from multiple x-ray sources is provided. The method comprises acquiring one or more CT axial projection datasets, wherein the CT axial projection datasets are acquired using less than a full scan of data. The method further comprises reconstructing the CT axial projection datasets to generate a reconstructed image volume. The reconstruction comprises backprojecting one or more voxels comprising the multi-axial CT dataset, along one or more projection views, based upon a cone-angle weight determined for the voxels, wherein the cone-angle weight for the voxels is determined along a longitudinal direction.

Abstract: Embodiments of the present invention include a method and apparatus for accurate cone beam reconstruction with source positions on a curve (or set of curves). The inversion formulas employed by embodiments of the method of the present invention are based on first backprojecting a simple derivative in the projection space and then applying a Hilbert transform inversion in the image space.

Abstract: A method and computer-readable medium for reconstructing an image volume of an object scanned in helical mode is provided. The method and computer-readable medium include obtaining one or more helical views corresponding to an image volume of an object and determining a plurality of discretized focal lengths within an imaging plane of the reconstructed field of view comprising the image volume. The method then comprises generating a plurality of circular scan sinograms for the plurality of discretized focal lengths. The plurality of circular scan sinograms are generated by interpolating the helical views. The method then comprises selecting one or more circular scan sinograms from the plurality of circular scan sinograms, based on the plurality of discretized focal lengths, wherein the selection is performed within a backprojection operation, for one or more image points within the imaging plane, over one or more circular views.

Abstract: A CT imaging system includes a computer that is programmed to rebin cone beam projection data into a series of two-dimensional sinograms based on an optimized ray consistency approach. The computer receives cone beam data from a detector array and is programmed to specify a plurality of view angles for the cone beam data. The computer selects a plurality of measured rays for each of the plurality of specified view angles, the plurality of measured rays having a view angle approximate to the specified view angle as determined by an optimized ray consistency. The computer also forms a two-dimensional sinogram for each of the plurality of specified view angles based on the selected plurality of measured rays. The computer then defines an image surface for each of the plurality of specified view angles based on the selected plurality of measured rays.

Abstract: A system and method for increasing apparent axial sampling resolution include acquiring CT data from scans which are offset due to a scan subject motion. Thus, in certain embodiments, a first scan or gantry rotation may be performed, followed by a subject shift. A second scan or gantry rotation may then be performed to acquire overlapping data which is offset from the data of the first scan. The system and method may also be incorporated in helical scanning techniques. By increasing the number of axial samples, some embodiments provide for reduced aliasing artifacts and improved x-ray interlacing.

Abstract: Systems and methods are provided for acquiring and reconstructing projection data that is mathematically complete or sufficient using a computed tomography (CT) system having stationary distributed X-ray sources and detector arrays. In one embodiment, a non-sequential activation is employed to acquire mathematically complete or sufficient projection data. In another embodiment, a distributed source is provided as a generally semicircular segment. In such an embodiment, an alternating activation scheme may be employed to allow one or more helices of image data to be acquired.

Abstract: Systems and methods are provided for acquiring and reconstructing projection data using a computed tomography (CT) system having stationary distributed X-ray sources and detector arrays. In one embodiment, a non-sequential activation of X-ray source locations on an annular source is employed to acquire projection data. In another embodiment, a distributed source is tilted relative to an axis of the scanner to acquire the projection data. In a further embodiment, a plurality of X-ray source locations on an annular source are activated such that the aggregated signals correspond to two or more sets of spatially interleaved helical scan data.

Abstract: Systems and methods are provided for reconstructing projection data that is mathematically complete or sufficient acquired using a computed tomography (CT) system. In one embodiment, a set of projection data representative of a sampled portion of a cylindrical surface is provided. The set of projection data is reconstructed using a suitable cone-beam reconstruction algorithm. In another embodiment, two or more sets of spatially interleaved helical projection data are processed using helical interpolation. The helically interpolated set of projection data is reconstructed using a two-dimensional axial reconstruction algorithm or a three-dimensional reconstruction algorithm.

Abstract: Systems and methods are provided for acquiring and reconstructing projection data that is mathematically complete or sufficient using a computed tomography (CT) system having stationary distributed X-ray sources and detector arrays. In one embodiment, a distributed source is provided as arcuate segments offset in the X-Y plane and along the Z-axis.

Abstract: Disclosed are embodiments of methods for reconstructing x-ray projection data (e.g., one or more sinograms) acquired using a multi-source, inverse-geometry computed tomography (“IGCT”) scanner. One embodiment of a first method processes an IGCT sinogram by rebinning first in “z” and then in “xy,” with feathering applied during the “xy” rebinning. This produces an equivalent of a multi-axial 3rd generation sinogram, which may be further processed using a parallel derivative and/or Hilbert transform. A TOM-window (with feathering) technique and a combined backprojection technique may also be applied to produce a reconstructed volume. An embodiment of a second method processes an IGCT sinogram using a parallel derivative and/or redundancy weighting. The second method may also use signum weighting, TOM-windowing (with feathering), backprojection, and a Hilbert Inversion to produce another reconstructed volume.