X-ray two-dimensional phase-contrast imaging method of single exposure

Abstract

The invention discloses an X-ray two-dimensional phase-contrast imaging method of single exposure. The method specifically includes following steps: during imaging, a detected object is arranged between a first encoding diaphragm M and an area array detector and close to the first encoding diaphragm M, the change of the intensity and the direction of the X-ray is caused by absorption and refraction of the X-ray by the detected object, the ray intensities I1, I2, I3 and I4 detected by pixels of the detector are changed, quantified phase and absorption information can be extracted by employing relative changes thereof, and two-dimensional phase-contrast imaging of the X-ray of single exposure is realized. The beneficial effects of the method are that the acquisition process is simplified, original secondary exposure is simplified as single exposure, the imaging time and the irradiation dose are reduced by 50% compared with that of the original method, the mode of single exposure can realize dynamic and online phase-contrast imaging, the realization of the phase-contrast CT technology of the X-ray is facilitated, two-dimensional phase-contrast imaging can be realized, and the object detail distinguishing capability and the defect detection capability are improved.

Description

technical field [0001] The invention belongs to the field of X-ray imaging, in particular to an X-ray two-dimensional phase-contrast imaging method that only needs a single exposure. Background technique [0002] In traditional X-ray imaging, the image contrast is based on the object’s absorption of X-rays. For strongly absorbing objects, it can give a higher image contrast, but for weakly absorbing objects, such as human soft tissue and fiber materials, the image contrast is low. In addition, for objects with similar absorption characteristics, the density resolution ability is limited, and it is difficult to accurately distinguish different materials. For example, in the early diagnosis of tumors, the detection sensitivity is low due to the close density of diseased tissue and normal tissue. X-ray Phase-Contrast Imaging (XPCI) can solve the above problems, giving higher image contrast and clearer object details. [0003] As an electromagnetic wave, X-rays will not only at...

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Problems solved by technology

[0006] However, at present, the edge illumination method needs to move the coded diaphragm once, perform an exposure at two positions respectively, and collect two original images to quantitatively extract phase and absorption information, resulting in complicated acquisition process and increased imaging time, which is not conducive to practical application

In addition, the edge illumination method only realizes one-dimensional phase contrast imaging. Since the phase information (refraction angle information in this method) has directionality, the refraction angle information can be extracted in both vertical and horizontal directions. One-dimensional phase contrast imaging Some detail information of the object will be lost, reducing the ability of defect detection and detail resolution

[0007] To sum up, the problems existing in the prior art are: two exposures are required in the imaging process, and two-dimensional phase-contrast imaging has not been realized

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