Patent US5396528A successfully refreshed from Google Patents.
US5396528A
Expired / Lapsed
US
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Tomographic image reconstruction using cross-plane rays
Assignee: General Electric Co
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Filing: 1991-06-28
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Granted: 1995-03-07
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Expires: 2011-06-28
Abstract
Abstract A CT apparatus employing a cone beam of x-rays reduces image artifacts by employing full as opposed to half scans of less than 360°. The present invention recognizes that rays of a cone beam that cross the imaging plane are not redundant with opposing rays in the scan, as is the case with the rays within the imaging plane. In a second embodiment, half scans of less than 360° are obtained using in-plane and cross-plane rays of the cone beam and the data from the in-plane rays is used to estimate the missing data from that collected with the cross-plane rays.
Inventors
- 👤 Hui Hu
- 👤 Carl R. Crawford
- 👤 Armin H. Pfoh
- 👤 Jiang Hsieh
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 12:41
CPC Classifications
A; A61; A61B; A61B6/00; A61B6/02; A61B6/03; A61B6/032; A61B6/40; A61B6/4064; A61B6/4085; Y; Y10; Y10S; Y10S378/00; Y10S378/901
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
156 words
A method of producing a tomographic image from projection data collected by a two-dimensional detector array receiving radiation along first rays perpendicular to a z-axis and second rays not perpendicular to the z-axis, said detector array producing first and second data indicating the intensities of the first and second rays respectively, comprising the steps of: a) collecting a first and second projection set comprising first and second projection data, respectively, over a range of gantry angles around the axis of less than 2π radians and for a number of z-axis positions; b) estimating from the first projection set, values for the second projection set at the z-axis positions but at gantry angles not within the range of gantry angles, to produce a third projection set; c) combining the second and third projection sets to produce a completed projection set; and d) reconstructing the completed projection set and the first projection set to produce the tomographic image.
Claim 2
Independent Claim
156 words
A method of producing a tomographic image from projection data collected by a two-dimensional detector array receiving radiation along first rays perpendicular to a z-axis and second rays not perpendicular to the z-axis, said detector array producing first and second data indicating the intensities of the first and second rays respectively, comprising the steps of: a) collecting a first and second projection set comprising first and second projection data, respectively, over a range of gantry angles around the axis of less than 2π radians and for a number of z-axis positions; b) estimating from the first projection set, values for the second projection set at the z-axis positions but at gantry angles not within the range of gantry angles, to produce a third projection set; c) combining the second and third projection sets to produce a completed projection set; and d) reconstructing the completed projection set and the first projection set to produce the tomographic image.
Claim 3
Dependent Claim
30 words
The method recited in claim 1 wherein the first rays are received over a fan angle and wherein the range of gantry angles equals π radians plus the fan angle.
Claim 4
Dependent Claim
56 words
A method as recited in claim 1 wherein step (b) comprises the steps of: reconstructing the first projection set to a three dimensional image set; and re-projecting the three dimensional image set along the second rays for each z-axis position at gantry angles not within the range of gantry angles to produce the third projection set.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1998-03-06 | 1998-09-05 | 1999-03-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-03-06 | 2002-09-05 | 2003-03-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-03-06 | 2006-09-05 | 2007-03-07 | $7700.00 | Window Closed / Lapsed |