Reduction of hitlist size in spiral cone beam CT by use of local radon origins
First Claim
1. A method of operating a 3D CT imaging apparatus having a cone beam radiation source and detector arrangement, for reconstructing an image of an object that is scanned by said source and detector arrangement, comprising the following steps:
- operating said source and detector arrangement at a plurality of source positions along a spiral scan path so as to acquire a corresponding plurality of sets of measurement data representative of radiation attenuation caused by said object, andprocessing the acquired measurement data using pre-calculated and stored image reconstruction processing information that was calculated on less that all of a plurality of vertically oriented coaxial φ
-planes that partition Radon space, for developing numerical values for Radon data samples on all of said φ
-planes that partition the Radon space.
4 Assignments
0 Petitions
Accused Products
Abstract
A method and apparatus for reconstructing an image of an object using a three dimensional (3D) computerized tomographic (CT) imager having a cone beam radiation source and detector arrangement for acquiring measurement data. The source and detector arrangement is operated at a plurality of source positions along a spiral scan path so as to acquire a corresponding plurality of sets of measurement data representative of radiation attenuation caused by the object. Image reconstruction processing information required for processing of the acquired measurement data in a Radon space partitioned by plurality of vertically oriented coaxial φ-planes for reconstructing the image, is pre-calculated and stored in a hitlist. The stored information is pre-calculated on less that all of the φ-planes, but due to a symmetry that is induced in the reconstruction processing, the stored information can be used for calculating Radon data for all of the φ-planes that partition the Radon space. The size of the hitlist is thus reduced by a factor equal to the number of φ-planes for which the stored information is re-used, e.g., 360 for 1/2 degree φ-plane spacing and storage of reconstruction processing information for a single φ-plane.
30 Citations
30 Claims
-
1. A method of operating a 3D CT imaging apparatus having a cone beam radiation source and detector arrangement, for reconstructing an image of an object that is scanned by said source and detector arrangement, comprising the following steps:
-
operating said source and detector arrangement at a plurality of source positions along a spiral scan path so as to acquire a corresponding plurality of sets of measurement data representative of radiation attenuation caused by said object, and processing the acquired measurement data using pre-calculated and stored image reconstruction processing information that was calculated on less that all of a plurality of vertically oriented coaxial φ
-planes that partition Radon space, for developing numerical values for Radon data samples on all of said φ
-planes that partition the Radon space. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
-
-
12. A method of operating a 3D CT imaging apparatus having a cone beam radiation source and detector arrangement, for reconstructing an image of an object that is scanned by said source and detector arrangement, comprising the following steps:
-
before the acquisition of measurement data during an imaging operation of the apparatus, pre-calculating and storing image reconstruction processing information required for processing of the acquired measurement data in Radon space partitioned by a set of vertically oriented co-axial φ
-planes to develop contributions to the final reconstruction of the image, which information is calculated on less than all of said φ
-planes; andduring the imaging operation of the apparatus, operating said source and detector arrangement at a plurality of source positions along a scan path so as to acquire a corresponding plurality of sets of said measurement data, and processing the acquired measurement data using said pre-calculated image reconstruction processing information on said single φ
-plane in a relative way to determine Radon data for other ones of the φ
-planes and reconstructing the image. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
-
-
26. A scanning and data acquisition apparatus for three dimensional (3D) computerized tomography (CT) imaging of an object in a field of view radially centered on a predetermined axis, comprising:
-
an energy source (10) for emitting energy in the form of a cone beam; an area detector (12) for detecting as measurement data cone beam energy after attenuation by passage through an object to be imaged; a manipulator (6) 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 (8) for defining the scan path as a plurality of spaced stages on a predetermined geometric surface surrounding the field of view, with each of a plurality of planes that pass through the field of view 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 sample points that sample a Radon space partitioned by a set of vertically oriented co-axial φ
-planes;image reconstruction processing means (18) including means for calculating Radon data for each of said Radon sample points by processing multiple ones of the sets of measurement data, for developing image data; and display means (28) responsive to said image data for displaying a reconstructed image of the object; wherein said image reconstruction processing means (18) includes a database (21) of reconstruction processing information that is calculated on less than all of said φ
-planes, which information is pre-calculated and stored before acquisition of the measurement data, and then used by said image reconstruction processing means (18) during imaging operation of said apparatus for facilitating processing of the measurement data to calculate the Radon data for all of the φ
-planes. - View Dependent Claims (27, 28, 29, 30)
-
Specification