US5251128A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Motion artifact reduction in projection imaging
Assignee: General Electric Co
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Filing: 1990-11-19
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Granted: 1993-10-05
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Expires: 2010-11-19
Abstract
Abstract An x-ray CT scanner acquires projection data from a series of views during a scan of a patient's chest. Movement of the patient's chest due to respiration is also sensed during the scan and this acquired motion data is employed along with a geometric model of chest motion to calculate factors which correct the acquired projection data and reduce motion artifacts in an image produced by back projecting the acquired projection data.
Inventors
- 👤 Carl R. Crawford
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 18:54
CPC Classifications
A; A61; A61B; A61B6/00; A61B6/58; A61B6/589; A61B5/00; A61B5/103; A61B5/11; A61B5/113; A61B5/72; A61B5/7203; A61B5/7207; A61B5/721; A61B6/02; A61B6/03; A61B6/032; A61B6/52; A61B6/5258; A61B6/5264; G; G06; G06T; G06T12/00; G06T12/10; A61B5/7235; A61B5/7253; A61B5/7257; G06T2211/00; G06T2211/40; G06T2211/412; G06T2211/421
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
143 words
A method for producing an image, of a patient, the steps comprising: performing a scan in which a plurality of sets of projection data are acquired, each set of projection data being a view of a physical characteristic of the patient as seen from a different projection angle (θ); acquiring a motion parameter with each set of acquired projection data, each acquired motion parameter being indicative of the position of the patient as the projection data is acquired; and back projecting each set of projection data to produce the image of the patient using a back projection formula which is modified by a displacement factor that has a value which is a function of the acquired motion parameter and a geometric model of patient motion; whereby artifacts produced in the image by movement of the patient from view-to-view during the scan are reduced.
Claim 2
Independent Claim
143 words
A method for producing an image, of a patient, the steps comprising: performing a scan in which a plurality of sets of projection data are acquired, each set of projection data being a view of a physical characteristic of the patient as seen from a different projection angle (θ); acquiring a motion parameter with each set of acquired projection data, each acquired motion parameter being indicative of the position of the patient as the projection data is acquired; and back projecting each set of projection data to produce the image of the patient using a back projection formula which is modified by a displacement factor that has a value which is a function of the acquired motion parameter and a geometric model of patient motion; whereby artifacts produced in the image by movement of the patient from view-to-view during the scan are reduced.
Claim 3
Dependent Claim
30 words
The method as recited in claim 1 in which the motion parameter acquired with each set of projection data indicates the position of the anterior chest wall of the patient.
Claim 4
Dependent Claim
63 words
The method as recited in claim 1 which includes: calculating a weighting factor for each set of projection data which is a function of the motion parameter acquired with the projection data and the projection angle (θ); and correcting each set of projection data by multiplying the projection data by its associated weighting factor prior to the back projection of the projection data.
Claim 5
Dependent Claim
65 words
The method as recited in claim 3 in which the motion parameter acquired with each set of projection data indicates the position of the anterior chest wall of the patient and the weighting factor is calculated using the acquired motion parameter and a reference value which indicates the position of the anterior chest wall of the patient at a point in the patient's respiratory cycle.
Claim 6
Dependent Claim
16 words
The method as recited in claim 3 in which the projection data is x-ray attenuation values.
Claim 7
Dependent Claim
55 words
The method as recited in claim 5 in which the view-to-view movement of the patient is due to respiration and a weighting factor is calculated based on a geometric model of the motion of the patient's chest cavity during respiration and the acquired motion parameter which indicates the position of the patient's anterior chest wall.
Claim 8
Dependent Claim
52 words
The method as recited in claim 6 in which the geometric model of patient motion is given by the formula f'(x,y)=f(α.sub.x +β.sub.x x, α.sub.y +β.sub.y y) where β x and β y are magnification factors and α x and α y are shift factors which indicate a point about which magnification occurs.
Claim 9
Dependent Claim
19 words
The method as recited claim 1 in which the set of projection data is acquired with parallel x-ray beams.
Claim 10
Dependent Claim
29 words
The method as recited in claim 1 in which the set of projection data is acquired with a curved array of x-ray detectors that receive a fan-beam of x-rays.
Claim 11
Dependent Claim
29 words
The method as recited in claim 1 in which the set of projection data is acquired with a flat array of x-ray detectors that receive a fan-beam of x-rays.
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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) | 1996-10-04 | 1997-04-05 | 1997-10-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-10-04 | 2001-04-05 | 2001-10-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-10-04 | 2005-04-05 | 2005-10-05 | $7700.00 | Window Closed / Lapsed |