Reconstruction of images in cone beam scanning with rectangular detector elements
First Claim
1. A method of computerized tomography comprising the steps of:
- (a) generating imaging energy;
(b) passing the imaging energy through an object of interest;
(c) using an array detector having non-square elements to detect said imaging energy as attenuated by passage through the object of interest to provide asymmetric projection data corresponding to an asymmetric grid in which at least a portion of the object of interest is disposed;
(d) converting said asymmetric projection data into distorted projection data which is symmetric corresponding to a symmetric grid, said distorted projection data representing projection data which would be obtained upon subjecting said portion of said object of interest to a distorting transformation which transforms said asymmetric grid into said symmetric grid;
(e) Generating distorted reconstruction image data by application of image reconstruction in symmetric geometry using said distorted projection data; and
(f) converting said distorted reconstructed image data into asymmetric reconstructed image data by correcting for distortions introduced by the converting from asymmetric projection data into distorted projection data.
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Accused Products
Abstract
Computerized tomography (CT) reconstruction of images is accomplished for asymmetric grids. After initial data acquisition and normalization, the asymmetric projection data is distorted by a compression process which effectively converts the data into symmetric data. The data may then be processed using Radon reconstruction procedures which convert projection data into object density functions. The object density functions or data which are provided are then subject to a stretching or extension procedure which compensates or reverses the initial distortion or compression. Cone beam imaging with asymmetric grids may be two-dimensional or three dimensional when utilizing the technique.
18 Citations
26 Claims
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1. A method of computerized tomography comprising the steps of:
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(a) generating imaging energy; (b) passing the imaging energy through an object of interest; (c) using an array detector having non-square elements to detect said imaging energy as attenuated by passage through the object of interest to provide asymmetric projection data corresponding to an asymmetric grid in which at least a portion of the object of interest is disposed; (d) converting said asymmetric projection data into distorted projection data which is symmetric corresponding to a symmetric grid, said distorted projection data representing projection data which would be obtained upon subjecting said portion of said object of interest to a distorting transformation which transforms said asymmetric grid into said symmetric grid; (e) Generating distorted reconstruction image data by application of image reconstruction in symmetric geometry using said distorted projection data; and (f) converting said distorted reconstructed image data into asymmetric reconstructed image data by correcting for distortions introduced by the converting from asymmetric projection data into distorted projection data. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A system for computerized tomography comprising:
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a source for generating cone beam imaging energy and passing it through an object of interest; a detector for detecting the cone beam image energy as attenuated by passage through the object of interest to provide cone beam data; (c) said detector being an array detector having non-square elements to detect said imaging energy as attenuated by passage through the object of interest to provide asymmetric projection data corresponding to an asymmetric grid in which at least a portion of the object of interest is disposed; (d) distortion means for converting said asymmetric projection data into distorted projection data which is symmetric corresponding to a symmetric grid, said distorted projection data representing projection data which would be obtained upon subjecting said portion of said object of interest to a distorting transformation which transforms said symmetric grid; (e) generation means for generating distorted reconstruction image data by application of image reconstruction in symmetric geometry using said distorted projection data; and (f) conversion means for converting said distorted reconstructed image data into asymmetric reconstructed image data by correcting for distortions introduced by the converting from asymmetric projection data into distorted projection data. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
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Specification