X-ray or gamma ray systems or devices – Specific application – Computerized tomography
Reexamination Certificate
2002-03-29
2003-11-25
Bruce, David V. (Department: 2882)
X-ray or gamma ray systems or devices
Specific application
Computerized tomography
C378S004000, C378S094000
Reexamination Certificate
active
06654442
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to computed tomographic (CT) imaging, and more particularly to methods and apparatus for weighting projection data acquired using a multi-slice CT imaging system.
For some known multi-slice helical scans, reconstructed with a fan-beam based algorithm, there is an error due to a cone beam effect of a projection sampling. The error in a reconstructed image increases with an increase of a distance of an image pixel to a system iso-center. Therefore, for pixels located near the system iso-center, a plurality of projection rays are near a reconstructed pixel location and an amount of cone beam error is relatively small. For pixels that are located further away from the system iso-center, a difference between the location where the projection sample passes and the location of the backprojected pixel is large and the amount of cone-beam error is relatively large.
BRIEF DESCRIPTION OF THE INVENTION
In one aspect, a method for weighting projection data is provided. The method includes selecting a region that includes a plurality of projection data samples, dividing the region into a plurality of equally sized sub-regions, and weighting the equally sized sub-regions using a location dependent z-smoothing weighting function.
In another aspect, a computer for weighting projection data acquired using a medical imaging system is provided. The imaging system includes a radiation source and a detector. The computer is programmed to select a region that includes a plurality of projection data samples, divide the region into a plurality of equally sized sub-regions, and weight the equally sized sub-regions using a location dependent z-smoothing weighting function.
In a further aspect, a computed tomographic (CT) imaging system for weighting projection data is provided. The CT system includes a radiation source, a detector array, and a computer coupled to the detector array and the radiation source and configured to select a region that includes a plurality of projection data samples, divide the region into a plurality of equally sized sub-regions, and weight the equally sized sub-regions using a location dependent z-smoothing weighting function.
REFERENCES:
patent: 5416815 (1995-05-01), Hsieh
patent: 5515409 (1996-05-01), Hsieh
patent: 5610964 (1997-03-01), Flohr et al.
patent: 5727041 (1998-03-01), Hsieh
patent: 5812628 (1998-09-01), Hsieh
patent: 6035012 (2000-03-01), Hsieh
patent: 6061419 (2000-05-01), Hsieh et al.
patent: 6061420 (2000-05-01), Strong et al.
patent: 6115487 (2000-09-01), Toth et al.
patent: 6134292 (2000-10-01), Hsieh
patent: 6215841 (2001-04-01), Hsieh
patent: 6233308 (2001-05-01), Hsieh
patent: 6339632 (2002-01-01), Besson
patent: 6418184 (2002-07-01), Wang et al.
patent: 6421411 (2002-07-01), Hsieh
Armstrong Teasdale LLP
Bruce David V.
GE Medical Systems Global Technology Company LLC
Horton Esq. Carl B.
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