Grating shearing phase contrast CT image-forming data acquisition and reconstruction method

Abstract

The invention discloses a grating shearing phase contrast CT imaging data acquisition and reestablishment method. The method comprises steps of utilizing a shearing technique of an analysis grating relative to a phase grating to obtain a displacement curve through measuring the displacement change of light intensity along with the analysis grating shearing, when the analysis grating is at the median point position of the displacement curve and the rotating shaft of the sample is parallel with the grid, acquiring CT projection data of a set of samples rotating by 360 DEG; selecting projection light ray data in opposite directions from the CT projection data of 360 DEG to perform a matching combination, separating the absorption projection data and refraction projection data of samples rotating by 180 DEG, reestablishing to form a parallel beam absorption projection data and refraction projection data of the samples rotating by 180 DEG; weighting the refraction projection data according to the rotational invariance to obtain multiple sets of 180 DEG parallel beam projection data satisfying the requirement of rotational invariance, and according to the Radon inverse transformation, reestablishing a three dimensional distribution of absorption coefficient, refractive index, first derivative of the refractive index and the second derivative of the refractive index.

Description

technical field [0001] The invention relates to the technical field of computerized tomography imaging, in particular to a method for collecting and reconstructing grating shear phase contrast CT imaging data. Background technique [0002] Traditional computed tomography (Computed Tomography, referred to as CT) is a great contribution of modern science and technology to human health. After more than 30 years of development, this technology has made remarkable progress in data acquisition, reconstruction methods and applications, and has become an indispensable tool in the fields of medicine, biology, archaeology, material science, safety inspection and industrial non-destructive testing. essential tool. The physical basis of the traditional CT principle is the difference in the absorption of X-rays by matter, and the mathematical basis is Radon transformation. Therefore, traditional CT technology is a combination of X-ray absorption contrast rotational projection imaging t...

AI Technical Summary

Problems solved by technology

It can be seen that the acquisition method of this projection data is more complicated than the traditional CT method.

Besides that, the reconstruction methods that have been proposed can only reconstruct the absorption coefficient and refractive index of the sample

Obviously, the current acquisition and reconstruction methods of grating-sheared phase-contrast CT projection data are not suitable for generalization to human imaging

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