Systems and methods for computed tomography image reconstruction

A method for computed tomography (CT) image reconstruction, comprising:

• obtaining a plurality of projection images of a subject, the plurality of projection images being generated according to scan data acquired by a CT scanner at a plurality of gantry angles, each of the plurality of projection images corresponding to one of the plurality of gantry angles;
• for each of the plurality of projection images, determining attenuation information of the projection image by transforming grey values of a plurality of pixels of the projection image;
• and
• reconstructing a CT image of the subject by simultaneously solving correction coefficients of the plurality of projection images such that a difference between estimated attenuation information of the plurality of projection images and the attenuation information of the plurality of projection images is minimized, the estimated attenuation information of the plurality of projection images relating to the CT image and the correction coefficients of the plurality of projection images.

A non-transitory computer-readable storage medium including instructions that, when accessed by at least one processor of a system, causes the system to perform a method, the method comprising:

• obtaining a plurality of projection images of a subject, the plurality of projection images being generated according to scan data acquired by a CT scanner at a plurality of gantry angles, each of the plurality of projection images corresponding to one of the plurality of gantry angles;
• for each of the plurality of projection images, determining attenuation information of the projection image by transforming grey values of a plurality of pixels of the projection image;
• and
• reconstructing a CT image of the subject by simultaneously solving correction coefficients of the plurality of projection images such that a difference between estimated attenuation information of the plurality of projection images and the attenuation information of the plurality of projection images is minimized, the estimated attenuation information of the plurality of projection images relating to the CT image and the correction coefficients of the plurality of projection images.

The non-transitory computer-readable storage medium of 19, wherein the reconstructing a CT image by simultaneously solving correction coefficients of the plurality of projection images comprises:

• constructing an estimated attenuation information function of the plurality of projection images, the estimated attenuation information function relating to the correction coefficients of the projection images, the coefficient matrix of the CT scanner, and the CT image;
• constructing a cost function of attenuation information configured to measure a difference between the estimated attenuation information of the plurality of projection images and the attenuation information of the plurality of projection images;
• and
• determining the CT image and the correction coefficients of the plurality of projection images by minimizing a value of the cost function of attenuation information.