Dual-energy X-ray phase-contrast imaging system without stepping device and realization method thereof

Abstract

The invention discloses a dual-energy X-ray phase-contrast imaging system without a stepping device and a realization method thereof. The system includes a dual-energy array X-ray source, a sample, aphase grating, a dual-energy analysis grating, and an X-ray detection device in order along an optical path, the dual-energy array X-ray source adjusts tube voltage to emit X-rays having different energies, and turns the X-rays into a series of individually coherent but mutually incoherent light; the phase grating separates the incident light into different diffraction orders, periodic interference fringes are formed at the dual-energy analysis grating, and moire fringes extraction phase information can be formed with the dual-energy analysis grating, and the X-ray detection device records moire fringe images. By adjusting the energy of X-rays, the dual-energy X-ray phase-contrast imaging system provided by the present invention utilizes the dual-energy analysis grating to convert different energy X-rays, and does not need to move the grating during imaging, the imaging steps are reduced, and the mechanical accuracy requirements are reduced.

Description

technical field [0001] The patent of the present invention relates to the field of X-ray imaging, especially a dual-energy X-ray phase-contrast imaging system without a stepping device and its realization method. Background technique [0002] The interaction between X-rays and matter can be expressed by the complex refractive index, that is, n=1-α+iβ, where β is the absorption factor and α is the phase factor, which respectively characterize the amplitude and phase changes of X-rays after passing through the object . Traditional X-ray imaging uses the X-ray absorption characteristics of substances to image objects, and is often used to detect substances composed of heavy metal materials such as metals. But for weakly absorbing substances such as articular cartilage, mammary glands, and polyethylene materials in the human body, which are composed of light elements such as C, H, O, and N, traditional X-ray imaging can hardly see their internal structures. After X-rays pass t...

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Problems solved by technology

[0004] However, the phase information extraction method based on "phase-stepping" commonly used in the world is too complicated, and the analysis grating or phase grating must be moved by a stepping device to obtain the background displacement curve and sample displacement curve, which requires stepping The movement of the device is on the order of microns, which increases the difficulty of mechanical control

Chen Bo proposed a two-step phase shift method in 2008, and Liu Xin proposed an arbitrary two-step shift method in 2013. Although the number of grating shift steps is getting smaller and smaller, the imaging system still needs a precise stepping platform, multiple steps and exposures Makes the imaging efficiency low and increases the radiation dose of the sample

The front and back projection method proposed by Zhu Peiping in 2010 does not require grating stepping. This method has made a breakthrough in phase contrast CT imaging, but it is very difficult to realize that the object or detector needs to be rotated precisely in the imaging system.

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