3D image reconstruction for helical partial cone beam data
First Claim
1. A method of image reconstruction from partial cone beam data comprising:
- (a) collecting the partial cone beam data in two-dimensional arrays, said collected data corresponding to rays of radiation diverging in two dimensions from a common vertex as the vertex travels along a curve with each element of the data related to line integrals of an object being reconstructed taken along each ray;
(b) defining a local coordinate system;
(c) pre-weighting the data;
(d) computing a one-dimensional convolution of the pre-weighted data in the local coordinate system along a direction which is tangential to the curve along which the vertex travels;
(e) weighting the convolved data; and
,(f) three-dimensionally backprojecting the weighted convolution.
1 Assignment
0 Petitions
Accused Products
Abstract
A method of image reconstruction from partial cone beam data includes collecting the partial cone beam data in two-dimensional arrays. The collected data corresponds to rays of radiation diverging in two dimensions from a common vertex as the vertex travels along a curve. Each element of the data represents a line integral of an object being reconstructed taken along each ray. The data is then pre-weighted and a local coordinate system is defined. A one-dimensional convolution of the pre-weighted data is computed in the local coordinate system along a direction which is tangential to the curve along which the vertex travels. Finally, the convolved data is weighted and three-dimensionally backprojected. In a preferred embodiment, the curve defines a helical path, and the kernel for the one-dimensional convolution of the pre-weighted data is a ramp convolver.
-
Citations
18 Claims
-
1. A method of image reconstruction from partial cone beam data comprising:
-
(a) collecting the partial cone beam data in two-dimensional arrays, said collected data corresponding to rays of radiation diverging in two dimensions from a common vertex as the vertex travels along a curve with each element of the data related to line integrals of an object being reconstructed taken along each ray; (b) defining a local coordinate system; (c) pre-weighting the data; (d) computing a one-dimensional convolution of the pre-weighted data in the local coordinate system along a direction which is tangential to the curve along which the vertex travels; (e) weighting the convolved data; and
,(f) three-dimensionally backprojecting the weighted convolution. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
-
-
12. A CT scanner comprising:
-
a first gantry which defines an examination region; a rotating gantry mounted on the first gantry for rotation about the examination region; a source of penetrating radiation arranged on the rotating gantry for rotation therewith, said source of penetrating radiation emitting a cone-shaped beam of radiation that passes through the examination region as the rotating gantry rotates; a subject support which holds a subject being examined at least partially within the examination region, wherein at least one of the first gantry and the subject support is translated such that the subject passes through the examination region while the rotating gantry is rotated and the source of penetrating radiation follows a helical path relative to the subject; a two-dimensional array of radiation detectors arranged to receive the radiation emitted from the source of penetrating radiation after it has traversed the examination region; a reconstruction processor which reconstructs images of the subject from data collected by the two-dimensional array of radiation detectors, said reconstruction processor including; a first data processor which pre-weights the data; a convolver which takes the data from the first data processor and performs a one-dimensional convolution on it in a local coordinate system along a direction which is tangential to the helical path; a second data processor which takes the data from the convolver and weights it; and
,a backprojector which takes the data from the second data processor and three-dimensionally backprojects it into an image memory; and
,a human viewable display which accesses the image memory to display reconstructed images of the subject. - View Dependent Claims (13, 14, 15, 16, 17, 18)
-
Specification