Voxel-driven spiral reconstruction for cone-beam computer tomography
First Claim
1. A method for generating images in computed tomography using 3D image reconstruction, the method comprising:
- scanning an examination object by moving a focus on a spiral focal track about the examination object using a conical beam emanating from the focus and using a detector for detecting the beam, the detector supplying output data corresponding to the detected radiation; and
reconstructing image voxels from the scanned examination object from the output data and reproducing attenuation coefficients of the respective voxel, each image voxel being reconstructed separately from projection data that include a projection angular range of at least 180°
, whereby a measured value filtered for each image voxel is accumulated only on the respective voxel, and an approximate weighting taking place for each voxel considered in order to normalize the projection data used relating to the respective voxel, whereinthe approximate weighting takes place on the projection data after interpolating the projection data and before filtering the projection data, the approximate weighting using voxel individual Parker weights.
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Abstract
A method is disclosed for generating computer tomography images using a 3D image reconstruction method. According to the method, to scan an object to be examined using a cone-shaped bundle of rays originating from a focal point and a planar, preferably multi-line detector for detecting the bundle of rays, the focal point is displaced along a spiral trajectory around the object to be examined. The detector delivers output data corresponding to the detected radiation and image voxels from the scanned examined object are reconstructed from the optionally pre-processed output data, the image voxels reflecting the attenuation coefficients of the respective voxel. Each image voxel is reconstructed separately from projection data, which covers a projection angular range of at least 108° and an approximate weighting is carried out for each voxel considered in order to standardize the projection data using the voxel.
21 Citations
17 Claims
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1. A method for generating images in computed tomography using 3D image reconstruction, the method comprising:
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scanning an examination object by moving a focus on a spiral focal track about the examination object using a conical beam emanating from the focus and using a detector for detecting the beam, the detector supplying output data corresponding to the detected radiation; and reconstructing image voxels from the scanned examination object from the output data and reproducing attenuation coefficients of the respective voxel, each image voxel being reconstructed separately from projection data that include a projection angular range of at least 180°
, whereby a measured value filtered for each image voxel is accumulated only on the respective voxel, and an approximate weighting taking place for each voxel considered in order to normalize the projection data used relating to the respective voxel, whereinthe approximate weighting takes place on the projection data after interpolating the projection data and before filtering the projection data, the approximate weighting using voxel individual Parker weights. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A CT unit for scanning an examination object, comprising:
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a beam emanating from at least one focus and a detector array having a multiplicity of distributed detector elements for detecting the rays of the beam, the at least one focus being movable relative to the examination object on at least one focal track that runs around the examination object and a detector array situated opposite; and means for reconstructing image voxels from the scanned examination object from the output data and reproducing attenuation coefficients of the respective voxel, each image voxel being reconstructed separately from projection data that include a projection angular range of at least 180°
, whereby a measured value filtered for each Image voxel is accumulated only on the respective voxel, and an approximate weighting taking place for each voxel considered in order to normalize the projection data used relating to the respective voxel, whereinthe approximate weighting takes place on the projection data after interpolating the projection data and before filtering the projection data, the approximate weighting using voxel individual Parker weights.
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Specification