A Multi-energy Spectral CT Image Reconstruction Method Based on Projection Estimation

Abstract

The invention discloses a multi-energy spectral CT image reconstruction method based on projection estimation, which is used for reconstructing multiple base material density images of a measured object. The method includes: using the traditional single-energy CT reconstruction algorithm to directly reconstruct the energy images of the measured object from the collected polychromatic projection data; calculating the line integral of each energy image along the ray directions of all other energy spectra, and estimating the The multicolor projection of the current energy spectrum in the direction is obtained to obtain the polychromatic projection with consistent geometric parameters; the multi-base material decomposition function is calibrated, and the estimated polychromatic projection with consistent geometric parameters is decomposed into line integrals of multiple base materials; The corresponding multi-substrate material density images are reconstructed from the multi-substrate material line integral respectively. The method of the invention is simple and practical, and is suitable for multi-energy spectral CT image reconstruction under the condition that the polychromatic projection geometric parameters are inconsistent. Compared with the prior art, high-quality images can be reconstructed only by using the measured projection data to estimate polychromatic projections with consistent geometric parameters.

Description

technical field [0001] The present invention relates to the technical field of X-ray CT imaging, in particular to a multi-energy spectrum CT image reconstruction method based on projection estimation. Background technique [0002] X-ray computed tomography (X-ray CT for short) is a technology that uses the principle of interaction between X-rays and matter to image the internal information of objects. X-ray CT technology is not only a conventional means of medical diagnosis and treatment, but also an important industrial support technology, which is widely used in the non-destructive testing of key components in various fields. Currently commonly used X-ray tubes cannot emit ideal single-energy X-ray beams, but emit polychromatic X-ray beams that obey a certain spectral distribution. The data collected by scanning is polychromatic projection data, so traditional CT is also called mono-energy spectrum. CT. Single-energy spectrum CT uses only one X-ray energy spectrum to sca...

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Problems solved by technology

This method has simple steps and high imaging quality, but it is only applicable to the situation where the polychromatic projection geometric parameters of various energy spectra are consistent, so it is not suitable for the current multi-energy spectral CT system

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