WO2020199194A1 - 一种x射线相位衬度成像方法 - Google Patents

一种x射线相位衬度成像方法 Download PDF

Info

Publication number
WO2020199194A1
WO2020199194A1 PCT/CN2019/081508 CN2019081508W WO2020199194A1 WO 2020199194 A1 WO2020199194 A1 WO 2020199194A1 CN 2019081508 W CN2019081508 W CN 2019081508W WO 2020199194 A1 WO2020199194 A1 WO 2020199194A1
Authority
WO
WIPO (PCT)
Prior art keywords
contrast imaging
image
grating
phase contrast
ray phase
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/CN2019/081508
Other languages
English (en)
French (fr)
Inventor
吴朝
魏文彬
高昆
王秋平
田扬超
陆亚林
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
University of Science and Technology of China USTC
Original Assignee
University of Science and Technology of China USTC
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by University of Science and Technology of China USTC filed Critical University of Science and Technology of China USTC
Priority to PCT/CN2019/081508 priority Critical patent/WO2020199194A1/zh
Publication of WO2020199194A1 publication Critical patent/WO2020199194A1/zh
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Images

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N23/00—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00
    • G01N23/02—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material
    • G01N23/04—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by transmitting the radiation through the material and forming images of the material
    • G01N23/041—Phase-contrast imaging, e.g. using grating interferometers

Definitions

  • the present disclosure relates to the field of imaging technology, and in particular to an X-ray phase contrast imaging method for rapid imaging with a large field of view.
  • the decrease in the real part ⁇ corresponds to phase modulation
  • the imaginary part ⁇ corresponds to absorption.
  • the falling speed of ⁇ is much greater than that of ⁇ .
  • X-ray grating phase contrast imaging due to its larger imaging field of view and better compatibility with conventional light sources, is considered to be a phase contrast that is likely to be used in clinical medical imaging.
  • Imaging method X-ray grating phase-contrast imaging has undergone two important developments. From 2002 to 2003, the X-ray Talbot interferometer was proposed [1-2] . Grating phase-contrast imaging was extended from visible light to X-ray, but it was still limited to synchrotron radiation sources. Or micro-focus light source. In 2006, the Talbot-Lau interferometer was proposed [3] , which greatly reduced the coherence requirements of the light source, making phase contrast imaging suitable for conventional X-ray sources, and providing basic conditions for the practical application of phase contrast imaging.
  • the projected image obtained by grating phase contrast imaging includes the absorption, refraction and scattering of the object.
  • the most commonly used information separation method at the laboratory stage is the phase stepping method [4] . This method requires at least three background images and three object images to complete the information separation. The background and object image, and then use Fourier analysis method to obtain the object's refraction information.
  • the phase stepping method can obtain high-quality images, but requires longer data acquisition time and more projected images. Compared with traditional absorption imaging, it not only increases the complexity of data collection, but also has the greater disadvantage of prolonging the exposure time and the object being exposed to high doses.
  • researcher Zhu Peiping from the Institute of High Energy Physics, Chinese Academy of Sciences proposed a fast and low-dose phase contrast imaging method [5] .
  • This method utilizes the conjugate characteristics of the front and back projections, successfully avoids the complex step movement of the grating in the traditional information recovery method, greatly improves the imaging speed, reduces the radiation dose, and realizes the phase contrast CT imaging compatible with the traditional CT scanning mode .
  • this method is based on the assumption of linear approximation of the waist position of the displacement curve, so the phase stepping curve of all pixels in the field of view is required to be synchronized, which increases the uniformity of the grating; the existing grating technology can only produce a small area that meets the front and back projection method. Grating, so the front and back projection method can only image small objects.
  • an X-ray phase contrast imaging method including: acquiring a background image and forming a background displacement curve; calculating a characteristic physical quantity of the background displacement curve; selecting an optimized stepping position according to the characteristic physical quantity , Collecting the forward image and the reverse image of the object based on the optimized stepping position; completing X-ray phase contrast imaging according to the forward image and the reverse image, the optimized stepping position and the characteristic physical quantity .
  • FIG. 1 is a flowchart of an X-ray phase contrast imaging method according to an embodiment of the disclosure.
  • Figures 2A-2I are the background images from the first step to the ninth step, respectively.
  • 3A-3C are schematic diagrams of average light intensity, visibility, and initial phase, respectively.
  • Fig. 4A is a forward image of an object
  • Fig. 4B is a reverse image of an object
  • Fig. 4C is a refraction image of an object obtained by a phase stepping method
  • Fig. 4D is a refraction image of an object obtained by an X-ray phase contrast imaging method according to an embodiment of the disclosure
  • Figure 4E is a comparison chart of refraction angle profile.
  • An embodiment of the present disclosure provides an X-ray phase contrast imaging method for rapid imaging with a large field of view.
  • This method uses an X-ray phase contrast imaging device for imaging.
  • the X-ray phase contrast imaging device includes: X-ray tube, source grating, beam splitting grating, analysis grating, X-ray detector.
  • X-ray tubes are used to generate X-rays.
  • the source grating is used for light splitting, dividing the large focus beam generated by the X-ray tube into narrow line light sources.
  • the beam splitting grating is used to generate self-imaging fringes at the analysis grating.
  • the analysis grating is used to generate moiré fringes with the self-imaging fringes of the beam splitting grating to amplify the changing information.
  • X-ray detectors are used to record the generated images.
  • the X-ray phase contrast imaging device may also include: an optical precision stage, a sample stage, an optical platform, and a control computer.
  • the source grating, beam splitting grating, and analysis grating are all mounted on the optical platform through an optical precision translation stage.
  • the X-ray phase contrast imaging method includes:
  • Step S101 collecting a background image and forming a background displacement curve.
  • the grating is controlled to step at equal intervals in the direction perpendicular to its grating line.
  • the number of steps of the grating is preferably 5-9 steps; each step of the grating further collects a background image.
  • the background image includes an image equal to the number of steps, and the asynchrony of each pixel of the background image forms a displacement curve.
  • FIGs 2A-2I there are 9 background images from the first step to the ninth step. After the background image is collected, move the raster back to its original position. Analyze the light intensity information of the background image to obtain the background displacement curve.
  • the traditional front and back projection method is based on an accurate background displacement curve, and the background image needs to be collected densely, and then the displacement curve is obtained by curve fitting.
  • the object image is collected at the half waist position, so the data collection is relatively complicated.
  • the X-ray phase contrast imaging method of the embodiment of the present disclosure does not need to collect background images densely, and only needs to collect background images equal to the number of grating steps, usually 5-9 frames, so the amount of data collection is small and relatively simple .
  • Step S102 Calculate the characteristic physical quantity of the background displacement curve.
  • the characteristic physical quantities include: average light intensity, visibility, and initial phase.
  • the front and back projection method needs to calculate the slope of the waist of the background displacement curve of each pixel, which involves fitting and differential calculation, which not only requires a large amount of calculation, but also has low calculation accuracy.
  • the characteristic physical quantity of the background displacement curve is calculated by the Fourier analysis method without calculating the slope of the displacement curve. This process can be calculated in parallel, which simplifies the calculation process and speeds up the calculation.
  • I b (x, y) is the gray value of the background image
  • a (x, y) is the average light intensity of the background displacement curve
  • V 0 (x, y) is the visibility of the background displacement curve
  • x g is the relative displacement of the grating
  • P 2 is the period of the analysis grating
  • three characteristic physical quantities of the average light intensity, visibility, and initial phase of the background displacement curve can be calculated based on the collected background image.
  • step S103 an optimized step position is selected according to the characteristic physical quantity of the background displacement curve, and a forward image and a reverse image of the object are collected based on the optimized step position.
  • the object When the object is imaged, it can be at any position of the background displacement curve. In order to optimize the imaging performance, the arbitrary position is usually selected closer to the waist position of the displacement curve. After the relative position of the grating (including the beam splitting grating and the analysis grating) is fixed at a position closer to the waist of the displacement curve, a circle of object images is collected to complete the phase contrast imaging.
  • the optimal step position is optimized
  • the third step position is selected as the optimized step position. Place the object in the optimized stepping position, and collect the forward and reverse images of the object, as shown in Figure 4A and Figure 4B, respectively.
  • step S104 the X-ray phase contrast imaging is completed according to the forward image and the reverse image, the optimized step position and the characteristic physical quantity.
  • This embodiment is based on the cosine function model of the background displacement curve, using the three characteristic physical quantities of the background displacement curve, the optimized step position, and the forward and reverse images of the object represented by the following two formulas, to further obtain the phase and absorption information of the object.
  • I s (x, y, ⁇ ) and I s (-x, y, ⁇ + ⁇ ) are the forward and reverse images of the object respectively
  • M(x, y, ⁇ ) and ⁇ (x, y, ⁇ ) are respectively Is the absorption signal and refraction signal of the object
  • d is the distance between the beam splitting grating and the analysis grating.
  • F the ratio of forward and reverse image projections, namely as well as
  • a (x, y) and B (x, y) are respectively defined as the cosine and sine of the object imaging step amplitude.
  • C(x, y) is the front projection light intensity of the object imaging step position added to the object refraction signal
  • D(x, y) is the back projection light intensity of the object imaging step position added to the object refraction signal.

Landscapes

  • Health & Medical Sciences (AREA)
  • Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
  • Radiology & Medical Imaging (AREA)
  • Physics & Mathematics (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Analysing Materials By The Use Of Radiation (AREA)

Abstract

一种X射线相位衬度成像方法，包括：采集背景图像并形成背景位移曲线（S101）；计算背景位移曲线的特征物理量（S102）；根据特征物理量选取优化步进位，基于优化步进位采集物体的正向图像和反向图像（S103）；根据正向图像和反向图像、优化步进位以及特征物理量完成X射线相位衬度成像（S104）。

Description

一种X射线相位衬度成像方法 技术领域
本公开涉及成像技术领域，尤其涉及一种X射线相位衬度成像方法，用于大视场快速成像。
背景技术
传统X射线吸收成像在无损检测、医学影像以及材料科学等领域得到广泛应用并发挥重要作用，然而对低原子系数物质成像图像衬度较低。X射线相衬成像方法，通过检测物体对X射线波前的相位调制，可以获得低原子序数物质较高衬度图像。这是因为物体对X射线的作用可用复数折射率n＝1-δ+iβ描述，实部减小量δ对应相位调制，虚部β对应吸收，随着原子序数的减小或成像能量的增加，β下降速度远大于δ的下降速度。在众多的相衬成像方法中，X射线光栅相衬成像，由于其较大的成像视场以及与常规光源较好的兼容性，被认为是一种很有可能应用于临床医学影像的相衬成像方法。X射线光栅相衬成像经历了两次重要发展，2002到2003年X射线Talbot干涉仪的提出 【1-2】，光栅相衬成像从可见光波段推广到X射线波段，然而仍局限于同步辐射光源或者微焦点光源。2006年，Talbot-Lau干涉仪的提出 【3】，大幅降低了对光源相干性要求，使得相衬成像适用于常规X射线源，为相衬成像的实际应用提供了基本条件。
尽管光栅相衬成像的应用前景被普遍看好，但是该方法仍然存在多方面的局限性，阻碍了其广泛应用。光栅相衬成像获得的投影像包含物体的吸收、折射以及散射。目前实验室阶段最常用的信息分离方法为相位步进方法 【4】，该方法至少需要三幅背景图像和三幅物体图像才能完成信息分离，通过等间距移动其中一块光栅获得多个位置处的背景和物体图像，再利用傅里叶分析方法获得物体的折射信息。
相位步进方法可以获得高质量图像，但是需要较长的数据采集时间和较多的投影图像。相比传统吸收成像，不仅增加了数据采集复杂度，更大的弊端是延长了曝光时间，物体受辐照剂量高。针对该问题，中科院高能物理研究所朱佩平研究员提出了一种快速低剂量的相衬成像方法 【5】。该方法利用正反投影共轭的特性，成功避免了传统信息恢复方法中光栅的复杂 步进运动，大大提高了成像速度、降低了辐射剂量，实现了与传统CT扫描模式兼容的相衬CT成像。然而，该方法基于位移曲线腰位线性近似的假设，因此要求视场内所有像素相位步进曲线同步，增加了光栅均匀性要求；利用现有光栅工艺只能制作满足正反投影方法的小面积光栅，因此正反投影方法只能对小物体成像。
[1].David C et al.Differential x-ray phase contrast imaging using a shearing interferometer，Appl.Phys.Lett.81：3287-3289(2002).
[2].Momose A et al.Demonstration of x-ray talbot interferometry，Jpn.J.Appl.Phys.42：L866-L868(2003).
[3].Pfeiffer F et al.Phase retrieval and differential phase-contrast imaging with low-brilliance x-ray sources，Nat.Phys.2：258-261(2006).
[4].Weitkamp T，et al.X-ray phase imaging with a grating interferometer，Opt.Express 13：6296-6304(2005).
[5]ZhuPP，etal.Low-dose，simple，and fast grating-based X-ray phase-contrast imaging，Proc.Natl.Acad.Sci.U.S.A.107，13576-13581(2010).
公开内容
根据本公开的一个方面，提供了一种X射线相位衬度成像方法，包括：采集背景图像并形成背景位移曲线；计算所述背景位移曲线的特征物理量；根据所述特征物理量选取优化步进位，基于所述优化步进位采集物体的正向图像和反向图像；根据所述正向图像和所述反向图像、所述优化步进位以及所述特征物理量完成X射线相位衬度成像。
为使本公开的上述目的、特征和优点能更明显易懂，下文特举优选实施例，并配合所附附图，作详细说明如下。
附图说明
为了更清楚地说明本公开实施例的技术方案，下面将对实施例中所需要使用的附图作简单地介绍。应当理解，以下附图仅示出了本公开的某些实施例，因此不应被看作是对范围的限定。对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据这些附图获得其他相关的附图。
图1为本公开实施例X射线相位衬度成像方法的流程图。
图2A-2I分别为第一步至第九步的背景图像。
图3A-3C分别为平均光强、可见度和初始相位的示意图。
图4A为物体的正向图像；图4B为物体的反向图像；图4C为相位步进方法获得物体的折射图像；图4D为本公开实施例X射线相位衬度成像方法获得物体的折射图像；图4E为折射角轮廓对比图。
具体实施方式
为使本公开的目的、技术方案和优点更加清楚明白，以下结合具体实施例，并参照附图，对本公开进一步详细说明。其中一些但并非全部的实施例将被示出。实际上，本公开的各种实施例可以许多不同形式实现，而不应被解释为限于此数所阐述的实施例。在不冲突的情况下，本公开中的实施例及实施例中的特征可以相互组合。
在本公开实施例提供一种X射线相位衬度成像方法，用于大视场快速成像。该方法利用X射线相位衬度成像装置进行成像。X射线相位衬度成像装置包括：X射线管、源光栅、分束光栅、分析光栅、X射线探测器。
X射线管用于产生X射线。源光栅用于分光，把X射线管产生的大焦点光束分成狭小的线光源。分束光栅用于在分析光栅处产生自成像条纹。分析光栅用于与分束光栅在此处的自成像条纹产生摩尔条纹以放大变化的信息。X射线探测器用于记录产生的图像。X射线相位衬度成像装置还可包括：光学精密位移台、样品台、光学平台以及控制计算机等。源光栅、分束光栅、分析光栅均通过光学精密位移台安装于光学平台之上。
如图1所示，所述X射线相位衬度成像方法，包括：
步骤S101，采集背景图像并形成背景位移曲线。
在本步骤中，在不放物体的情况下，控制光栅在垂直于其栅线方向等间距步进。本实施例中，光栅的步进数优选为5-9步；光栅每步进一步，采集一幅背景图像。背景图像包括与步进数相等的图像，背景图像每个像素点的不同步组成一条位移曲线。如图2A-2I所示，为第一步至第九步的9幅背景图像。背景图像采集完成后，将光栅移回原位置。分析背景图像的光强信息，得到背景位移曲线。
传统正反投影方法基于精确的背景位移曲线，需密采集背景图像，再通过曲线拟合获得位移曲线，在半腰位置处采集物体图像，因此数据采集相对较复杂。而本公开实施例的X射线相位衬度成像方法，无需密采集背 景图像，只需采集与光栅步进数相等的背景图像，通常5-9幅即可，因此数据采集量小，相对更简单。
步骤S102，计算背景位移曲线的特征物理量。
所述特征物理量包括：平均光强、可见度以及初始相位。
正反投影方法需要计算每个像素的背景位移曲线腰位处斜率，涉及拟合和微分计算，不仅计算量大，而且计算精度不高。本公开实施例的X射线相位衬度成像方法，通过傅里叶分析方法计算背景位移曲线特征物理量，无需计算位移曲线斜率。该过程可以并行计算，简化了计算过程，加快了计算速度。
背景图像用余弦函数表示为：
Figure PCTCN2019081508-appb-000001
其中I b(x，y)为背景图像灰度值，a(x，y)为背景位移曲线的平均光强，V 0(x，y)为背景位移曲线的可见度，x g为光栅相对位移，p 2为分析光栅的周期，
Figure PCTCN2019081508-appb-000002
为背景位移曲线的初始相位。本实施例根据采集的背景图像可计算出背景位移曲线的平均光强、可见度以及初始相位三个特征物理量。
设I bn(x，y)为第n步采集的背景图像，其中1≤n≤N，N≥3，N为步进总数，则光栅相对位移x g＝np 2/N，则三个特征物理量可分别通过如下公式计算：
Figure PCTCN2019081508-appb-000003
Figure PCTCN2019081508-appb-000004
Figure PCTCN2019081508-appb-000005
其中函数arg为取辐角，图3A-图3C所示为三个特征物理量的示意图。
步骤S103，根据背景位移曲线的特征物理量选取优化步进位，基于该优化步进位采集物体的正向图像和反向图像。
物体成像时，可以处于背景位移曲线的任意位置。为优化成像性能，该任意位置通常选取较接近位移曲线腰位的位置。光栅(包括分束光栅与分析光栅)相对位置固定在较接近位移曲线腰位的位置后，采集一圈物体图像完成相衬成像。
根据步骤S102中所计算出的初始相位，如图3C所示的初始相位，优化选取优化步进位
Figure PCTCN2019081508-appb-000006
本实施例中选取第3步进位为优化步进位。将物体置于该优化步进位，并采集物体的正向图像和反向图像，分别如图4A和图4B所示。
步骤S104，根据正向图像和反向图像、优化步进位以及特征物理量完成X射线相位衬度成像。
本实施例基于背景位移曲线余弦函数模型，利用背景位移曲线三个特征物理量、优化步进位以及如下两式表示的物体正、反向图像，可进一步获得物体的相位和吸收信息。
Figure PCTCN2019081508-appb-000007
Figure PCTCN2019081508-appb-000008
其中I s(x，y，φ)、I s(-x，y，φ+π)分别为物体正、反向图像，M(x，y，φ)、θ(x，y，φ)分别为物体的吸收信号和折射信号，
Figure PCTCN2019081508-appb-000009
为优化步进位，d为分束光栅与分析光栅间的间距。
定义F为正、反向图像投影之比，即
Figure PCTCN2019081508-appb-000010
以及
Figure PCTCN2019081508-appb-000011
Figure PCTCN2019081508-appb-000012
其中A(x，y)和B(x，y)分别定义为物体成像步进位振幅余弦量和正弦量。
即可推导出如下的信息提取公式：
当A(x，y)-FA(-x，y)＝0且B(x，y)+FB(-x，y)≠0时
Figure PCTCN2019081508-appb-000013
Figure PCTCN2019081508-appb-000014
其中：
Figure PCTCN2019081508-appb-000015
Figure PCTCN2019081508-appb-000016
其中C(x，y)为物体成像步进位加入物体折射信号的正投影光强，D(x，y)为物体成像步进位加入物体折射信号的反投影光强。
当A(x，y)-FA(-x，y)≠0时，
Figure PCTCN2019081508-appb-000017
其中角度γ 0和β 0为
Figure PCTCN2019081508-appb-000018
Figure PCTCN2019081508-appb-000019
将采集的正反向物体图像，优化步进位以及三个特征物理量代入公式(7)-(13)，即可得到X射线相位衬度成像的相位信息和吸收信息，完成X射线相位衬度成像。
如图4C-图4E所示，为了验证本实施例的正确性，采集了9步相位步进的物体图像，作为对比例的相位步进方法获得物体的折射图像如图4C所示，本实施例获取的折射图像如图4D所示。并对两种方法获得的结果 进行对比，如图4E所示，两种方法的结果吻合度高。
至此，已经结合附图对本公开实施例进行了详细描述。需要说明的是，在附图或说明书正文中，未绘示或描述的实现方式，均为所属技术领域中普通技术人员所知的形式，并未进行详细说明。此外，上述对各元件和方法的定义并不仅限于实施例中提到的各种具体结构、形状或方式，本领域普通技术人员可对其进行简单地更改或替换。

Claims (11)

  1. 一种X射线相位衬度成像方法，其中，包括：
    采集背景图像并形成背景位移曲线；
    计算所述背景位移曲线的特征物理量；
    根据所述特征物理量选取优化步进位，基于所述优化步进位采集物体的正向图像和反向图像；
    根据所述正向图像和所述反向图像、所述优化步进位以及所述特征物理量完成X射线相位衬度成像。
  2. 根据权利要求1所述的X射线相位衬度成像方法，其中，所述采集背景图像包括：
    在不放物体的情况下，控制光栅在垂直于光栅栅线方向等间距步进，所述光栅每步进一步，采集一幅背景图像；所述光栅的步进数大于等于3步。
  3. 根据权利要求1所述的X射线相位衬度成像方法，其中，所述特征物理量包括：平均光强、可见度以及初始相位。
  4. 根据权利要求1所述的X射线相位衬度成像方法，其中，利用傅里叶分析方法计算所述背景位移曲线的特征物理量。
  5. 根据权利要求1所述的X射线相位衬度成像方法，所述背景图像表示为：
    Figure PCTCN2019081508-appb-100001
    其中I b(x，y)为背景图像灰度值，a(x，y)为背景位移曲线的平均光强，V 0(x，y)为背景位移曲线的可见度，x g为光栅相对位移，p 2为分析光栅的周期，
    Figure PCTCN2019081508-appb-100002
    为背景位移曲线的初始相位。
  6. 根据权利要求5所述的X射线相位衬度成像方法，其中，所述平均光强为：
    Figure PCTCN2019081508-appb-100003
    其中I bn(x，y)为第n步采集的背景图像，1≤n≤N，N≥3，N为步进 总数。
  7. 根据权利要求5所述的X射线相位衬度成像方法，其中，所述可见度为：
    Figure PCTCN2019081508-appb-100004
  8. 根据权利要求5所述的X射线相位衬度成像方法，其中，所述初始相位为：
    Figure PCTCN2019081508-appb-100005
    其中，函数arg为取辐角。
  9. 根据权利要求1所述的X射线相位衬度成像方法，其中，所述物体的正向图像和反向图像为：
    Figure PCTCN2019081508-appb-100006
    Figure PCTCN2019081508-appb-100007
    其中I s(x，y，φ)为物体的正向图像，I s(-x，y，φ+π)为物体的反向图像，M(x，y，φ)、θ(x，y，φ)分别为物体的吸收信号和折射信号，
    Figure PCTCN2019081508-appb-100008
    为所述优化步进位，d为分束光栅与分析光栅间的间距。
  10. 根据权利要求9所述的X射线相位衬度成像方法，其中，所示正向图像与所述反向图像的投影之比为F，即
    Figure PCTCN2019081508-appb-100009
    以及
    Figure PCTCN2019081508-appb-100010
    Figure PCTCN2019081508-appb-100011
    其中A(x，y)和B(x，y)分别为物体成像步进位的振幅余弦量和正弦量。
  11. 根据权利要求10所述的X射线相位衬度成像方法，其中，当A(x，y)-FA(-x，y)＝0且B(x，y)+FB(-x，y)≠0时
    Figure PCTCN2019081508-appb-100012
    Figure PCTCN2019081508-appb-100013
    其中：
    Figure PCTCN2019081508-appb-100014
    Figure PCTCN2019081508-appb-100015
    其中，C(x，y)为物体成像步进位加入物体折射信号的正投影光强，D(x，y)为物体成像步进位加入物体折射信号的反投影光强；
    当A(x，y)-FA(-x，y)≠0时，
    Figure PCTCN2019081508-appb-100016
    其中角度γ 0和β 0为：
    Figure PCTCN2019081508-appb-100017
    Figure PCTCN2019081508-appb-100018
PCT/CN2019/081508 2019-04-04 2019-04-04 一种x射线相位衬度成像方法 Ceased WO2020199194A1 (zh)

Priority Applications (1)

Application Number Priority Date Filing Date Title
PCT/CN2019/081508 WO2020199194A1 (zh) 2019-04-04 2019-04-04 一种x射线相位衬度成像方法

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/CN2019/081508 WO2020199194A1 (zh) 2019-04-04 2019-04-04 一种x射线相位衬度成像方法

Publications (1)

Publication Number Publication Date
WO2020199194A1 true WO2020199194A1 (zh) 2020-10-08

Family

ID=72664657

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2019/081508 Ceased WO2020199194A1 (zh) 2019-04-04 2019-04-04 一种x射线相位衬度成像方法

Country Status (1)

Country Link
WO (1) WO2020199194A1 (zh)

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN201191275Y (zh) * 2007-11-23 2009-02-04 同方威视技术股份有限公司 一种x射线光栅相衬成像系统
CN101467889A (zh) * 2007-12-26 2009-07-01 中国科学院高能物理研究所 光栅剪切相位衬度ct成像数据采集和重建方法
CN102221565A (zh) * 2010-04-19 2011-10-19 清华大学 X射线源光栅步进成像系统与成像方法
CN102509094A (zh) * 2011-11-25 2012-06-20 哈尔滨工业大学深圳研究生院 基于结构光的嵌入式3d指纹采集方法及系统
CN105675631A (zh) * 2016-01-05 2016-06-15 合肥泰禾光电科技股份有限公司 一种快速扇束几何相位衬度ct成像装置和方法
CN107144581A (zh) * 2017-05-05 2017-09-08 北京航空航天大学 基于横向错位吸收光栅的x射线光栅差分相位衬度成像方法及装置
US9795350B2 (en) * 2012-12-21 2017-10-24 Carestream Health, Inc. Material differentiation with phase contrast imaging

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN201191275Y (zh) * 2007-11-23 2009-02-04 同方威视技术股份有限公司 一种x射线光栅相衬成像系统
CN101467889A (zh) * 2007-12-26 2009-07-01 中国科学院高能物理研究所 光栅剪切相位衬度ct成像数据采集和重建方法
CN102221565A (zh) * 2010-04-19 2011-10-19 清华大学 X射线源光栅步进成像系统与成像方法
CN102509094A (zh) * 2011-11-25 2012-06-20 哈尔滨工业大学深圳研究生院 基于结构光的嵌入式3d指纹采集方法及系统
US9795350B2 (en) * 2012-12-21 2017-10-24 Carestream Health, Inc. Material differentiation with phase contrast imaging
CN105675631A (zh) * 2016-01-05 2016-06-15 合肥泰禾光电科技股份有限公司 一种快速扇束几何相位衬度ct成像装置和方法
CN107144581A (zh) * 2017-05-05 2017-09-08 北京航空航天大学 基于横向错位吸收光栅的x射线光栅差分相位衬度成像方法及装置

Similar Documents

Publication Publication Date Title
Morgan et al. X-ray phase imaging with a paper analyzer
US10481110B2 (en) Radiographic image generating device
Koehler et al. Slit‐scanning differential x‐ray phase‐contrast mammography: Proof‐of‐concept experimental studies
CN102221565B (zh) X射线源光栅步进成像系统与成像方法
CN108680589B (zh) 基于横向错位光栅的三维锥束计算机层析成像方法及装置
JP6529968B2 (ja) Ｘ線格子位相コントラストイメージング装置及び方法
CN101371786B (zh) 一种x射线图像三维重构的方法及系统
US10779776B2 (en) Apparatus for X-ray imaging an object
WO2013126296A1 (en) Apparatus and method for x-ray phase contrast imaging
CN105606633A (zh) X射线相衬成像系统与成像方法
JP2012516739A (ja) 格子を用いたシングルステップの低線量ｘ線位相コントラストイメージング
Qiao et al. Single-shot x-ray phase-contrast and dark-field imaging based on coded binary phase mask
JP2012200567A (ja) 放射線撮影システム及び放射線撮影方法
CN116297578B (zh) X射线相位定量成像技术与测量方法
CN108469443A (zh) 基于二维错位吸收光栅的x射线光栅差分相位衬度成像方法及装置
CN108896584A (zh) 基于双探测器光栅干涉仪的单次曝光x射线暗场成像方法
Wu et al. Prototype system of noninterferometric phase-contrast computed tomography utilizing medical imaging components
CN104254786B (zh) 计算断层摄影成像方法和系统
CN105675631A (zh) 一种快速扇束几何相位衬度ct成像装置和方法
Spindler et al. Simulation framework for X-ray grating interferometry optimization
JP2013031784A (ja) Ｘ線撮像装置およびｘ線撮像方法
Diemoz et al. A simplified approach for computed tomography with an X-ray grating interferometer
CN104535595B (zh) 一种用于x射线光栅相位衬度成像的背景扣除方法
WO2012169426A1 (ja) 放射線撮影システム
CN110133010B (zh) 一种x射线相位衬度成像方法

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 19922273

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 19922273

Country of ref document: EP

Kind code of ref document: A1

32PN Ep: public notification in the ep bulletin as address of the adressee cannot be established

Free format text: NOTING OF LOSS OF RIGHTS PURSUANT TO RULE 112(1) EPC (EPO FORM 1205A DATED 22/04/2022)

122 Ep: pct application non-entry in european phase

Ref document number: 19922273

Country of ref document: EP

Kind code of ref document: A1