X ray multi-energy-spectrum CT (Computed Tomography) finite angle scanning and image iterative reconstruction method

Abstract

The invention discloses an X ray multi-energy-spectrum CT (Computed Tomography) finite angle scanning and image iterative reconstruction method, which comprises the following steps that: applying theX rays of a plurality of energy spectrums to scan an object in a respective finite angel range, and obtaining the projection data of a tested object under each energy spectrum; on the basis of the projection data, independently reconstructing the image of each tested object under each energy spectrum; utilizing the consistency of the tested object and the complementarity of the reconstructed imageunder each energy spectrum, designing a combined regularization method to effectively remove an artifact caused by finite angle scanning in the reconstructed image under each energy spectrum, and calculating to obtain a high-quality reconstructed image; and therefore, applying an image domain decomposition method or a projection domain decomposition method to calculate to obtain the base materialimage or the dual-effect image of the tested object. The method is suitable for the image reconstruction of the multi-energy-spectrum CT under a finite angle scanning condition, the dosage of the X ray is lowered, scanning time is shortened, and the method has the advantages of high reconstructed image quality, high rate of convergence and the like.

Description

technical field [0001] The invention relates to the technical field of X-ray CT imaging, in particular to an X-ray multi-energy spectrum CT limited-angle scanning and image iterative reconstruction method. Background technique [0002] X-ray Computed Tomography (X-ray CT for short) has been widely used in medical diagnosis, industrial non-destructive testing, biological sample testing, security inspection and other fields. At present, the commonly used X-ray tubes emit polychromatic X-ray beams that obey a certain spectral distribution, rather than ideal single-energy X-ray beams. The projection data collected are polychromatic projection data, so traditional CT is also called single-energy spectrum CT. . Single-energy spectrum CT only uses one X-ray energy spectrum to scan the measured object at different angles, and uses the principle of interaction between X-rays and matter to obtain the projection data of the measured object at these angles, and use these projection dat...

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Problems solved by technology

[0005] The present invention provides an X-ray multi-energy spectrum CT limited-angle scanning mode and an image iterative reconstruction method, which are used to solve the problem that the traditional multi-energy spectrum CT reconstruction algorithm is difficult to reconstruct the measured object when the scanning angle is limited in the prior art. Problems with material density images, double effect images, etc.

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