Computed tomography method utilizing a conical radiation beam
AssigneeU.S. Philips Corporation
InventorsMichael Grass, Roland Proksa
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Abstract
The invention relates to a computed tomography method where the examination zone is scanned by means of a conical radiation beam. The reconstruction volume can be enlarged by reconstructing the absorption of voxels in a first sub-volume by means of a first reconstruction algorithm and that of voxels in a second sub-volume by means of a second reconstruction algorithm, the assignment of the voxels to the sub-volumes being performed in such a manner that the secondary conditions for the reconstruction algorithms used for these sub-volumes are satisfied.
Claims7
A computed tomography method comprising:
- generating a conical radiation beam which traverses an examination zone or an object present therein,
- generating a relative motion, including a rotation about an axis of rotation between the radiation beam and the examination zone or the object,
- acquiring, during the relative motion, measuring data which are dependent on the intensity in the radiation beam to the other side of the examination zone,
- reconstructing the spatial distribution of the absorption within the examination zone from the measuring data acquired by the detector unit, wherein the step of reconstructing further comprises:
- defining at least one first and one second sub-volume within the overall volume traversed by the radiation beam,
- reconstructing the spatial distribution of the absorption within the first sub-volume by means of a first reconstruction algorithm, and
- reconstructing the spatial distribution of the absorption within the second sub-volume by means of a second reconstruction algorithm which deviates from the first reconstruction algorithm.
A computed tomography apparatus comprising:
- a radiation source for emitting a conical radiation beam which traverses an examination zone or an object present therein,
- a two-dimensional detector unit which is connected to the radiation source and serves for the acquisition of measuring data which is dependent on the intensity in the radiation beam at the other side of the examination zone,
- a drive device for realizing a relative motion, including a rotation about an axis of rotation between the radiation source and the detector unit on the one side and the examination zone, or the object, on the other side, and
- a reconstruction unit for the reconstruction of the spatial distribution of the absorption within the examination zone from the measuring data acquired by the detector unit, wherein the reconstruction unit further comprises means for
- defining at least one first and one second sub-volume within the overall volume traversed by the radiation beam,
- reconstructing the spatial distribution of the absorption within the first sub-volume by means of a first reconstruction algorithm, and
- reconstructing the spatial distribution of the absorption within the second sub-volume by means of a second reconstruction algorithm which deviates from the first reconstruction algorithm.
Dependencies are inferred from the claim text.