X-ray or gamma ray systems or devices – Specific application – Computerized tomography
Patent
1998-12-11
2000-10-10
Bruce, David V.
X-ray or gamma ray systems or devices
Specific application
Computerized tomography
378 10, 378 15, 378901, A61B 603
Patent
active
06130929&
ABSTRACT:
Computed tomographic ("CT") x-ray scanning yields a discrete set of measurement values that are line integrals of attenuation coefficients .mu.(r), which attenuation coefficients may be obtained using suitable reconstruction techniques. Electronic beam computed tomograph ("EBCT") systems add error to the reconstructed attenuation coefficients owing to their unique cone geometry. A method is provided that reduces such errors. At least two scans, "tilted" by the system cone angle, collect data in the neighborhood of a reference plane normal to the system z-axis. These scans are rebinned into parallel projections, and a series expansion is considered for variation of .mu.(r) in the vicinity of the reference plane. If a first order series is considered sufficient, then two scans are required to estimate the slope A of the variation in data. The data can then be corrected for the "tilt" and line integrals on the reference plane normal to the z-axis obtained. If a second order series is necessary, two parameters A and B need to be determined from three suitably spaced scans, and the data corrected to obtain line integrals on the reference plane. The data can be corrected in the spatial domain by integration or preferably in the transform domain by differentiation. Once the line integrals are obtained on the reference plane, standard two-dimensional CT reconstruction be carried out to obtain the correct attenuation coefficients. The result is to provide a reconstructed image with reduced cone beam error.
REFERENCES:
patent: 5491734 (1996-02-01), Boyd et al.
Feldkamp, L.A., et al., "Pratical Cone Beam Algorithm", Journal of Optical Soc. Am., vol. A6, pp. 612-619, 1984.
Schaller, S., "3D Fourier Image Reconstruction", Erlanger (1994) (doctoral dissertation, translated from German).
Schaller, S.,et al., "New, efficient Fourier-reconstruction method for approximate image reconstruction in spiral cone-beam CT at small cone angles".
Bruce David V.
Imatron Inc.
LandOfFree
Method for eliminating artifacts in scanning electron beam compu does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for eliminating artifacts in scanning electron beam compu, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for eliminating artifacts in scanning electron beam compu will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2262367