A X-ray CT Image Reconstruction Method Based on Low Dose Projection Data Filtering

Abstract

Disclosed is an X-ray computed tomography (CT) image reconstruction method based on low dose projection data filtering. The method includes the following steps: (1), system parameters of CT equipment and projection data in low-dose scan protocols are acquired; (2), variance estimation is carried out on the projection data acquired in the step (1); (3), filter design is carried out, filtering is carried out on the projection data acquired in the step (1), and projection data after the filtering are acquired; and (4), CT image reconstruction is carried out on the projection data acquired in the step (3) after the filtering, and a final CT image is acquired. The step (3) specifically includes: filter form design (I) is carried out; and the projection data in the step (1) are put into the formula (I), and the formula (I) is executed circularly and the circular execution is stopped when preset times are reached, and an acquired iterative operation result is the final projection data after the filtering. By means of the X-ray CT image reconstruction method based on the low dose projection data filtering, image noise and image artifacts can be greatly reduced, original image resolution can be well maintained at the same time, and high-quality CT image reconstruction is achieved finally.

Description

technical field [0001] The invention relates to an image reconstruction method of medical images, in particular to an X-ray CT image reconstruction method based on projection data filtering. Background technique [0002] X-ray CT scanning has been widely used in clinical medical imaging diagnosis, but excessive X-ray radiation dose during CT scanning may cause cancer risk. In order to reduce the damage to users, how to minimize the dose of X-rays has become one of the key technologies in the field of medical CT imaging. [0003] In order to reduce the X-ray radiation dose, the easiest way used in the prior art is to reduce the tube current and scanning time during the CT scanning process. However, due to the reduction of tube current and scanning time, the projection data will contain a lot of noise, and the quality of the image reconstructed based on the traditional filtered back projection method will be severely degraded, which is difficult to meet the needs of clinical ...

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Problems solved by technology

[0005] When reconstructing a CT image of the same size, the iterative reconstruction method based on the statistical model needs to iteratively solve the objective function dozens or even hundreds of times, resulting in a significant increase in image reconstruction time

The time spent is much longer than the traditional analytical reconstruction method, which cannot meet the clinical real-time imaging requirements of CT

[0006] However, the analytical reconstruction method based on projection data filtering in the prior art will inevitably lead to the loss of original image detail information during the projection data denoising process. resulting in a decrease in the resolution of the corresponding CT image

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