EP0467532A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Computed tomography system
Assignee: General Electric Co
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Filing: 1991-06-19
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Granted: —
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Expires: 2011-06-19
Abstract
Abstract A CT apparatus for reducing aliasing in reconstructed images uses an x-ray tube (10) with a translatable focal spot (11) to double the spatial sampling rate, over that achieved by a conventional CT machine, by acquiring a first and second projection corresponding to two different focal spot positions. The amount of gantry rotation (dt) and the translation distance (W) of the focal spot are coordinated so that the projections are interlaced and the resulting combined projection is geometrically indistinguishable from a conventional projection with twice the spatial sampling rate. The distance the focal spot is translated is further adjusted to eliminate redundant projections and provide adequate data acquisition time.
Inventors
- 👤 Albert Henry Roger Lonn
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 15:19
CPC Classifications
A; A61; A61B; A61B6/00; A61B6/02; A61B6/03; A61B6/032; A61B6/40; A61B6/4021
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
170 words
A method of acquiring projection data on a tomographic imaging system having an opposed x-ray source and a plurality of periodically spaced x-ray detector elements mounted on a gantry rotatable about a center, said system useable for acquiring a series of projections of an imaged object along rays having an angle T and a radius r with respect to the center, and where the x-ray source is movable with respect to the gantry generally within a plane of gantry rotation along a tangent to the gantry rotation, comprising the steps of: initiating the acquisition of a first projection at a first gantry angle with the x-ray source in a first position with respect to the gantry; rotating the gantry by an angle dT during the first projection; wobbling the x-ray source by distance w to a second position with respect to the gantry; and initiating the acquisition of a second projection, where angle dT and distance w are chosen such that the second projection is interlaced with the first projection.
Claim 2
Dependent Claim
63 words
The method of claim 1 wherein the angle dT equals sP R d and the wobble distance w equals sP R s R d where: P is the spacing between detector elements; S is a desired spatial sampling frequency; R s is the distance between the x-ray source and the center; and R d is the distance between the detector and the center.
Claim 3
Dependent Claim
7 words
The method of claim 2 wherein s=1/2.
Claim 4
Dependent Claim
7 words
The method of claim 2 wherein s=3/2.
Claim 5
Dependent Claim
157 words
An CT apparatus for imaging a body comprising: a gantry rotatable about a center; an x-ray source mounted on said gantry for producing x-ray radiation from a first and second locations with respect to the gantry and generally within the plane of rotation of the gantry and along the tangent to the gantry rotation; a detector comprised of a plurality of periodically spaced detector elements having a separation distance P for measuring projection data from radiation received along rays from the x-ray source, said rays having angle T and a radius r with respect to the center; an x-ray control means for causing the x-rays from the x-ray source to shift between the two different locations to produce first and second projection data; and a gantry control means for coordinating the shifting of the x-ray source by the x-ray control means with the rotation of the gantry so that the first and second projection data are interlaced.
Claim 6
Dependent Claim
83 words
The apparatus of claim 5 wherein the gantry controller rotates the gantry by angle dT equal to sP R d between the shifting of the x-rays from the first to the second location by wobble distance w equal to P R s R d where: P is the spacing between detector elements; s is the desired spatial sampling frequency; R s is the distance between the x-ray source and the center; and R d is the distance between the detector and the center.
Claim 7
Dependent Claim
7 words
The apparatus of claim 6 wherein s=1/2.
Claim 8
Dependent Claim
7 words
The apparatus of claim 6 wherein s=3/2.
References Cited (Backward Citations)
No citation records indexed.
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