CT (Computed Tomography) value correcting method for cone-beam CT

Abstract

The invention discloses a CT (Computed Tomography) value correcting method for cone-beam CT. The CT value correcting method comprises the following steps: scanning air, a water phantom and a bone tissue body phantom under different scanning conditions to respectively obtain projection data; reestablishing an image; removing noise and artifacts by adopting a polynomial fitting method based on a template image; selecting a plurality of interested regions and calculating a mean value of an attenuation coefficient and a standard deviation of the attenuation coefficient; obtaining the value range of the attenuation coefficient and taking the attenuation coefficient of maximum occurrence probability; fitting the attenuation coefficients of the air, the water phantom and the bone tissue body phantom under the different scanning conditions with corresponding ideal CT values to obtain respective fitting curves; performing CT scanning and image reestablishment on a scanned material; obtaining a CT value image according to a material attenuation coefficient image and a fitting curve and finishing the CT value correction. According to the CT value correcting method disclosed by the invention, image noise and artifact can be effectively reduced, the reestablished image of single material reaches the uniformity to the great degree, the precision of the attenuation coefficient of the material becomes higher and further high accuracy for the fitting of the curve of the CT value and the material attenuation coefficient is realized.

Description

Technical field [0001] The present invention relates to the technical field of medical devices, in particular to a CT value correction method for cone beam CT. Background technique [0002] CT examination is an indispensable examination method in formulating surgical plans and setting radiation doses. The correct CT diagnosis can only be concluded through the lesion information provided by high-quality CT photos. Therefore, the control of the quality of CT images has become a great concern The problem. In analyzing CT images, the changes in tissue density can be effectively understood by measuring CT values. If the CT value is not accurate enough, it is easy to cause misjudgment and cause the operation to fail. In radioactive RT therapy, the CT value is used as a reference for the radiation dose provided by the doctor. The larger the CT value, the greater the radiation dose required. Conversely, the smaller the CT value, the smaller the radiation dose required. If the CT value...

AI Technical Summary

Problems solved by technology

Establish the corresponding relationship between the actual test CT value and its ideal CT value under various scanning conditions. In actual operation, multiple state curves need to be established, and the process is complicated and time-consuming.

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