4D-CBCT reconstruction method combining motion estimation and space-time tensor enhanced representation

Abstract

The invention discloses a 4D-CBCT reconstruction method combining motion estimation and space-time tensor enhancement representation, and belongs to the technical field of computed tomography. The method comprises the following steps: firstly, carrying out phase division on 4DCBCT projection data of a patient by utilizing a respiration signal, reconstructing by adopting an EMTV algorithm to obtainan initial image, and estimating an initial deformation vector field by utilizing the initial image; then, introducing the space-time tensor enhancement representation into an image reconstruction model, constraining the reconstructed image after deformation vector field processing, and obtaining an updated reconstructed image; then, establishing a symmetrical motion estimation model by utilizingthe updated reconstructed image and the projection data to obtain a new deformation vector field; and finally, alternately updating the reconstructed image and the deformation vector field through iteration to obtain a high-quality reconstructed image. Motion blur and aliasing artifacts in 4D-CBCT reconstruction can be effectively relieved, more details are reserved, the contrast ratio of the reconstructed image is improved, and the 4D-CBCT is promoted to be used in the field of image guided radiotherapy.

Description

technical field [0001] The invention relates to the technical field of computed tomography, and more specifically, relates to a 4D-CBCT reconstruction method that combines motion estimation and space-time tensor enhanced representation. Background technique [0002] With the rapid development of medical technology, tumor radiotherapy has entered the era of precision, that is, precise positioning, precise planning and precise radiotherapy. In the process of radiotherapy, the positioning and displacement errors between the tumor and the surrounding normal tissues will affect the accuracy of radiotherapy, thereby affecting the final treatment effect. In this process, image quality assurance is particularly important, which is the prerequisite for precise tumor positioning and tracking. To solve this problem, people combine radiotherapy equipment and imaging equipment to realize fully automatic tumor positioning and tracking, determine the position and movement trajectory of th...

AI Technical Summary

Problems solved by technology

[0007] The purpose of the present invention is to overcome the problems of low image quality, loss of tissue details, and low contrast in the 4D-CBCT reconstruction method in the prior art, and intends to provide a 4D-CBCT reconstruction method that combines motion estimation and spatiotemporal tensor enhanced representation , called Motion Estimation and Spatiotemporal Tensor Enhanced representation Reconstruction (MESTER for short), without changing the existing CBCT hardware cost, by combining motion estimation and spatiotemporal tensor in reconstruction Enhanced representation method to suppress image blurring and loss of details caused by respiratory movement and angle loss, improve 4D-CBCT reconstruction image quality, and finally provide real-time and accurate image information for doctors during radiotherapy, thereby improving radiotherapy accuracy and curative effect

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