CT image reconstruction from fan-parallel data

被引:24
作者
Besson, G [1 ]
机构
[1] GE, Appl Sci Lab, Milwaukee, WI 53201 USA
关键词
CT reconstruction; fan-parallel geometry; arcsin image reconstruction; data rebinning;
D O I
10.1118/1.598533
中图分类号
R8 [特种医学]; R445 [影像诊断学];
学科分类号
1002 ; 100207 ; 1009 ;
摘要
Third generation fan-beam computerized tomography (CT) scanners acquire data one entire projection at a time. The associated filtered-backprojection algorithm requires a computationally expensive pixel-dependent weight factor in the backprojector. Methods of simplifying the reconstruction include rebinning the fan-beam data to parallel projections. The rebinning can be separated into two steps: azimuthal interpolation, leading to the fan-parallel geometry, where data are unevenly spaced on radial lines through the origin of Radon space, and a subsequent axial interpolation to parallel data. Under appropriate view and projection sampling conditions, the azimuthal interpolation can be replaced by either data resorting or projection channel-dependent delays. This article investigates an arcsin algorithm to reconstruct an image directly from the fan-parallel data. Although it is shown that the algorithm cannot be exact, a natural approximation is described. The pre- and postconvolution weights, and the reconstruction filter, are derived analytically. imaging results demonstrate that arcsin image quality matches that of parallel reconstruction. The fan-parallel reconstruction method eliminates the resolution-compromising axial interpolation and the costly pixel-dependent backprojection weight. Further, an arcsin detector design is proposed for direct parallel reconstruction from fan-beam data. (C) 1999 American Association of Physicists in Medicine. [S0094-2405(99)00103-4].
引用
收藏
页码:415 / 426
页数:12
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