Normalized Correction Method of X-ray Hardening Artifacts Based on Helicoid Phantom

Abstract

The invention relates to two phantoms with the same inventive concept, and provides an X-ray CT beam hardening calibration method based on the phantoms. One of the X-ray CT beam hardening calibration phantoms includes upper and lower parts, the upper part is a measuring structure, the main body is a cylinder, the outer edge of the bottom surface of the cylinder is an Archimedes spiral, and there is a stepped circular hole in the center. The diameter of the round hole in the adjacent layer is equal to or slightly larger than the difference between the maximum and minimum radius of the spiral. The parameters of the outer spiral and the number of inner layers are modified according to the actual measurement requirements; the lower part is an auxiliary structure, which is divided into a holding area from top to bottom , Centering area and clamping area, the surface of the holding area is rough and easy to operate; the centering area is a smooth cylinder, used for detector centering operation; during the operation, select the corresponding inner layer radius according to the required penetration distance , first place the centering area in the auxiliary structure in the center of the field of view for centering, and then move down the phantom to place the inner step corresponding to the selected radius in the measurement structure in the center of the field of view for 360-degree scanning.

Description

technical field [0001] The invention relates to a method and phantom for multi-energy X-ray CT beam hardening calibration Background technique [0002] Computed Tomography (abbreviated as CT), which mainly uses multi-angle X-ray scanning and computer reconstruction algorithms to obtain the three-dimensional structure of the measured object, plays an important role in industrial non-destructive testing. Its imaging principle uses Lambert-Beer's law, that is, when a single-energy X-ray penetrates a single homogeneous object, the negative logarithm of the ratio of the outgoing light intensity to the incident light intensity is proportional to the penetration distance of the ray in the object, thus CT detection can obtain the internal structure and composition information of substances. [0003] At present, the reconstruction algorithm used in the CT field is based on single-energy ray imaging in principle, but the X-rays used in actual detection are multi-energy rays, so the r...

AI Technical Summary

Problems solved by technology

One disadvantage of this method is that it needs to move the sample for multiple measurements, which is not only time-consuming, but also easily introduces errors during the displacement process.

Another disadvantage is that the calibration results are poorly adaptable to different ray source voltages, and need to be re-measured when the voltage changes

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