Fast fan-beam geometric phase contrast CT imaging device and method

Abstract

The invention discloses a fast fan-beam geometric phase contrast CT imaging device and method. The phase contrast CT imaging device includes an X light source, a phase grating, a sample platform, an analysis grating and a detector. The invention adopts a cylindrical optical element, Large field of view imaging can be realized under the illumination of conventional X light sources; the invention uses cylindrical optical elements that match the geometry of light to avoid the problem of rays being blocked at large incident angles, greatly improving the imaging field of view, and at the same time combining the idea of ​​square projection, In the traditional CT scanning mode, the phase information of the object is successfully extracted, and the fast phase contrast CT imaging is completed.

Description

Technical field [0001] The invention relates to the technical field of X-ray imaging, in particular to a fast fan beam geometric phase contrast CT imaging device and method. Background technique [0002] Since Roentgen discovered X-rays, X-rays have been widely used in medical imaging, industrial non-destructive testing and other fields. However, traditional X-ray absorption imaging is not ideal for imaging soft tissues with low atomic coefficients. Under X-ray irradiation, the refractive index of an object can be expressed as a complex number as n=1-δ-iβ, where δ is the decrease in the real part of the refractive index and β is the imaginary part of the refractive index. As the atomic coefficient decreases, δ and β decrease, but in the hard X-ray band, the decrease in the real part of the refractive index δ of the soft tissue with low atomic coefficient is about 1000 times the imaginary part β. Therefore, it is theoretically possible to obtain an image with higher contrast than...

AI Technical Summary

Problems solved by technology

The traditional grating phase-contrast imaging method uses the phase-stepping method to complete information separation and extraction, but the phase-stepping method needs to move the grating laterally, which is incompatible with the CT scanning method, which leads to the disadvantages of long phase-contrast CT imaging time and high dose, and cannot be used for the heart. isokinetic tissue imaging

In 2010, researcher Zhu Peiping published a fast grating phase contrast imaging method (PNAS107, 13576–13581, 2010) in the Proceedings of the National Academy of Sciences of the United States (PNAS107, 13576–13581, 2010), which is the front and back projection method. Applied to parallel beam illumination geometry, usually synchrotron X-ray sources, which greatly limits its practical application

Images