CT (Computed Tomography) iterative image reconstruction method

Abstract

The invention discloses a CT (Computed Tomography) iterative image reconstruction method, which can be applied to precise sectional image reconstruction in incomplete projection data situations such as low X-ray tube current, under-sampling or limited angle. The method comprises steps of projection-driven iterative calculation, adaptively-determined ordered subset number, adaptive weight, and distance-driven orthographic projection and back projection calculation. A set of all projection data processed by each time of iterative calculation at each projection angle is firstly divided into a plurality of ordered subsets and each subset undergoes the following steps of distance-driven orthographic projection, subtraction with real projection data and weighting, distance-driven back projection and to-be-reconstructed image correction. In the scanning modes of low X-ray tube current, under-sampling or limited angle, a reconstructed image which can fully meet imaging clinical diagnosis demands can be obtained, the method can be self-sufficiently applied to CT imaging aiming at reducing the X-ray radiation dose or can be used for front-end processing of other CT image reconstruction algorithm.

Description

technical field [0001] The present invention relates to the technical field of CT image reconstruction, in particular to the following CT iterative image reconstruction technology: the tomographic image can be reconstructed accurately enough from incomplete projection data with low X-ray tube current and under-sampling or limited angle, so that the CT can be significantly reduced. On the premise of checking the X-ray radiation dose, it provides a CT iterative image reconstruction method that is fully suitable for the needs of imaging clinical diagnosis. Background technique [0002] X-ray CT (Computed Tomography, computerized tomography) scanning is one of the indispensable basic means of clinical imaging examination. However, since the world's first CT machine was officially installed and used for more than 40 years in 1971, people have been troubled by the X-ray radiation dose and the carcinogenicity of X-ray radiation, because they are directly related to the health and s...

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Problems solved by technology

[0005] Based on the poor anti-noise ability of previous CT image reconstruction algorithms, high requirements for data integrity, poor self-adaption and engineering practicability, the reconstructed image quality is not yet fully suitable for the needs of clinical imaging in imaging, so that it cannot reduce the X-ray rate of CT examination. In view of the disadvantages of obtaining good application effects in the radiation dose problem, the present invention combines the characteristics of classic iterative CT image reconstruction algorithms, and combines the distance-driven forward / reverse projection calculation strategy and technical ideas such as ordered subsets and self-adaptability, and proposes A CT iterative image reconstruction method as described below

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