CN110133010B - X-ray phase contrast imaging method - Google Patents

X-ray phase contrast imaging method Download PDF

Info

Publication number
CN110133010B
CN110133010B CN201910274368.XA CN201910274368A CN110133010B CN 110133010 B CN110133010 B CN 110133010B CN 201910274368 A CN201910274368 A CN 201910274368A CN 110133010 B CN110133010 B CN 110133010B
Authority
CN
China
Prior art keywords
image
grating
background
phase contrast
contrast imaging
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.)
Active
Application number
CN201910274368.XA
Other languages
Chinese (zh)
Other versions
CN110133010A (en
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 CN201910274368.XA priority Critical patent/CN110133010B/en
Publication of CN110133010A publication Critical patent/CN110133010A/en
Application granted granted Critical
Publication of CN110133010B publication Critical patent/CN110133010B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

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

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

The present disclosure provides an X-ray phase contrast imaging method, comprising: step 1, collecting a background image and forming a background displacement curve; step 2, calculating the characteristic physical quantity of the background displacement curve in the step 1; step 3, selecting an optimized step according to the characteristic physical quantity of the background displacement curve calculated in the step 2, and acquiring a forward image and a reverse image of the object based on the optimized step; and step 4, finishing X-ray phase contrast imaging according to the forward image and the backward image, the optimized step and the characteristic physical quantity in the step 3.

Description

X-ray phase contrast imaging method
Technical Field
The invention relates to the technical field of clinical medical imaging, nondestructive testing and X-ray CT imaging, in particular to an X-ray phase contrast imaging method which is used for large-field-of-view rapid imaging.
Background
The traditional X-ray absorption imaging is widely applied and plays an important role in the fields of nondestructive testing, medical imaging, material science and the like, but has lower contrast on the imaging image of low-atomic-coefficient substances. The X-ray phase contrast imaging method can obtain high-contrast images of low-atomic-number substances by detecting the phase modulation of an object on the X-ray wavefront. This is because the effect of the object on X-rays can be described by the complex index n ═ 1- + i β, the decrease in the real part corresponds to phase modulation, the imaginary part β corresponds to absorption, and the rate of β fall is much greater than the rate of fall as the atomic number decreases or the imaging energy increases. Among the phase contrast imaging methods, X-ray grating phase contrast imaging is considered to be a phase contrast imaging method that is likely to be applied to clinical medical images due to its large imaging field of view and its good compatibility with conventional light sources. X-ray grating phase-contrast imaging has undergone two important developments, and the X-ray Talbot interferometer proposed in 2002-2003【1-2】Raster phase-contrast imaging is generalized from the visible to the X-ray bands, but is still limited to synchrotron radiation sources or microfocus sources. In 2006, the Talbot-Lau interferometer was proposed【3】The method greatly reduces the requirement on the coherence of the light source, so that the phase contrast imaging is suitable for the conventional X-ray source, and provides basic conditions for the practical application of the phase contrast imaging.
Although the application prospect of grating phase-contrast imaging is generally good, the method still has various limitations, and the wide application of the method is prevented. The shadowgraph image obtained by the grating phase-contrast imaging contains the absorption, refraction and scattering of the object. The most common information separation method in laboratory stage at present is the phase stepping method【4】The method can complete information separation only by at least three background images and three object images, obtains the background and object images at a plurality of positions by moving one grating at equal intervals, and obtains the refraction information of the object by utilizing a Fourier analysis method.
The phase stepping method can obtain high quality images but requires a longer data acquisition time and more projection images. Compared with the traditional absorption imaging, the method not only increases the complexity of data acquisition, but also has the greater defects of prolonging the exposure time and ensuring high dose of the irradiated object. Aiming at the problem, the high-energy physical research institute of Chinese academy of sciences jupeipin researchers provide a rapid low-dose phase contrast imaging method【5】. The method successfully avoids the complex step motion of the grating in the traditional information recovery method by utilizing the forward and backward projection conjugation characteristic, greatly improves the imaging speed, reduces the radiation dose and realizes the phase contrast CT imaging compatible with the traditional CT scanning mode. However, this method is based on the assumption of linear approximation of the displacement curve waist, thus requiring synchronization of all pixel phase stepping curves within the field of view, increasing the grating uniformity requirement; the existing grating process can only be used for manufacturing a small-area grating meeting the front-back projection method, so that the front-back projection method can only image a small object.
[1].David C et al.Differential x-ray phase contrast imaging using ashearing 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-contrastimaging with low-brilliance x-ray sources，Nat.Phys.2：258-261(2006).
[4].Weitkamp T，et al.X-ray phase imaging with a gratinginterferometer，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).
Disclosure of Invention
Technical problem to be solved
Based on the above problems, the present disclosure provides an X-ray phase contrast imaging method, so as to alleviate the technical problems in the prior art that all pixel displacement curves in an imaging field are required to be phase-synchronized and located at the waist position when an object image is acquired, the requirements on grating uniformity and mechanical precision are extremely high, and the method is only suitable for small field imaging and cannot be applied to medical imaging.
(II) technical scheme
The present disclosure provides an X-ray phase contrast imaging method, comprising:
step 1, collecting a background image and forming a background displacement curve;
step 2, calculating the characteristic physical quantity of the background displacement curve in the step 1;
step 3, selecting an optimized step according to the characteristic physical quantity of the background displacement curve calculated in the step 2, and acquiring a forward image and a reverse image of the object based on the optimized step; and
and 4, finishing X-ray phase contrast imaging according to the forward image, the reverse image, the optimized step and the characteristic physical quantity in the step 3.
In an embodiment of the present disclosure, the acquiring a background image includes:
under the condition of not placing an object, controlling the grating to step at equal intervals in the direction vertical to the grating line of the grating, and acquiring a background image when the grating steps one step; the stepping number of the grating is more than or equal to 3.
In the embodiments of the present disclosure, the characteristic physical quantities include: average light intensity, visibility, and initial phase.
In the embodiment of the present disclosure, the characteristic physical quantity of the background displacement curve is calculated by using a fourier analysis method.
In an embodiment of the present disclosure, the background image is represented as:
Figure BDA0002018401640000031
wherein L isb(x, y) is the gray value of the image collected by the detector, a (x, y) is the average light intensity of the background displacement curve, V0(x, y) is the visibility of the background displacement curve, xgFor relative displacement of gratings, p2In order to analyze the period of the grating,
Figure BDA0002018401640000032
the initial phase of the background displacement curve.
In the disclosed embodiment, the average light intensity is:
Figure BDA0002018401640000033
wherein IbnAnd (x, y) is the background image acquired in the nth step, N is more than or equal to 1 and less than or equal to N, N is more than or equal to 3, and N is the total number of steps.
In the disclosed embodiments, the visibility is:
Figure BDA0002018401640000034
in the embodiment of the present disclosure, the initial phase is:
Figure BDA0002018401640000035
wherein the function arg is the argument.
In an embodiment of the present disclosure, the forward image and the backward image of the object are:
Figure BDA0002018401640000041
Figure BDA0002018401640000042
wherein Is(x, y, phi) is a forward image of the object, Is(-x, y, phi + pi) is the reverse image of the object, M (x, y, phi) and theta (x, y, phi) are the absorption signal and the refraction signal of the object respectively,
Figure BDA0002018401640000043
d is the distance between the beam splitting grating and the analysis grating for optimized stepping position grating relative displacement.
In the disclosed embodiment, the ratio of the projection of the forward image to the backward image is F, i.e. F
Figure BDA0002018401640000044
And
Figure BDA0002018401640000045
Figure BDA0002018401640000046
where A (x, y) and B (x, y) are defined as the object imaging step amplitude cosine and sine quantities, respectively.
In the disclosed embodiment, when a (x, y) -FA (-x, y) is 0 and B (x, y) + FB (-x, y) ≠ 0
Figure BDA0002018401640000047
Figure BDA0002018401640000048
Wherein:
Figure BDA0002018401640000049
Figure BDA00020184016400000410
c (x, y) is the forward projection light intensity of the object imaging step added to the object refraction signal, and D (x, y) is the back projection light intensity of the object imaging step added to the object refraction signal;
when A (x, y) -FA (-x, y) ≠ 0,
Figure BDA0002018401640000051
wherein the angle gamma0And beta0Comprises the following steps:
Figure BDA0002018401640000052
Figure BDA0002018401640000053
(III) advantageous effects
From the above technical solution, it can be seen that the X-ray phase contrast imaging method provided by the present disclosure has at least one or some of the following beneficial effects:
(1) the background data acquisition, calculation and information extraction processes are simple;
(2) the requirement on the uniformity of the grating is reduced, so that a large imaging field of view can be realized;
(3) meanwhile, the method has the characteristics of quick and large-field imaging, and is favorable for promoting the practical application of phase contrast imaging.
Drawings
Fig. 1 is a flowchart of an X-ray phase contrast imaging method according to an embodiment of the present disclosure.
FIG. 2 is 9 background images of 9 phase steps performed in step 1 of an X-ray phase contrast imaging method according to an embodiment of the present disclosure; wherein fig. 2A-2I correspond to the background images of steps 1-9, respectively.
FIG. 3 is a schematic diagram of an average light intensity, a visibility and an initial phase of a displacement curve of each pixel point in a field of view according to an embodiment of the disclosure; wherein FIG. 3A is a graph of average light intensity; fig. 3B is a visibility diagram, and fig. 3C is an initial phase diagram.
FIG. 4A is a forward image of an object; FIG. 4B is a reverse image of an object; FIG. 4C is a phase stepping method to obtain a refraction image of an object; FIG. 4D is a schematic diagram of a refractive image of an object obtained by an X-ray phase contrast imaging method according to an embodiment of the disclosure; fig. 4E is a graph comparing the refraction angle profiles at the white dotted line shown in fig. 4A.
Detailed Description
The embodiment of the disclosure provides an X-ray phase contrast imaging method for large-field-of-view fast imaging. The method utilizes an X-ray phase contrast imaging device for imaging. An X-ray phase contrast imaging apparatus includes: the X-ray detector comprises an X-ray tube, a source grating, a beam splitting grating, an analysis grating and an X-ray detector.
An X-ray tube is used to generate X-rays. The source grating is used for splitting light, and a large focus light beam generated by the X-ray tube is split into narrow line light sources. The beam splitting grating is used to generate self-imaging fringes at the analyzer grating. The analyzer grating is used to generate moir é fringes with the self-imaging fringes at the beam-splitting grating to amplify the varying information. The X-ray detector is used for recording the generated image. The X-ray phase contrast imaging apparatus may further include: an optical precision displacement table, a sample table, an optical platform, a control computer and the like. The source grating, the beam splitting grating and the analysis grating are all arranged on the optical platform through the optical precision displacement platform.
For the purpose of promoting a better understanding of the objects, aspects and advantages of the present disclosure, reference is made to the following detailed description taken in conjunction with the accompanying drawings.
In an embodiment of the present disclosure, an X-ray phase contrast imaging method is provided, as shown in fig. 1, the X-ray phase contrast imaging method includes:
step 1, collecting a background image and forming a background displacement curve;
in this step, under the condition of not placing an object, the grating is controlled to step at equal intervals (one integral part of the grating period) in the direction vertical to the grating line of the grating, so that the background image is acquired and a background displacement curve is formed. In this embodiment, the number of steps of the grating is preferably 5 to 9 steps; and acquiring a background image by stepping the grating by one step. The background image comprises images with the same stepping number, and each pixel point of the background image is asynchronous to form a displacement curve. As shown in fig. 2A-2I, 9 background images for the first to ninth steps. And after the background image is acquired, the grating is moved back to the original position. And analyzing the light intensity information of the background image to obtain a background displacement curve.
The traditional forward and backward projection method is based on an accurate background displacement curve, needs to acquire a background image densely, acquires a displacement curve through curve fitting, and acquires an object image at a half-waist position, so that data acquisition is relatively complex. The X-ray phase contrast imaging method disclosed by the embodiment of the disclosure does not need to closely acquire background images, and only needs to acquire the background images with the same number as the grating steps, generally 5-9 background images, so that the data acquisition amount is small and the method is relatively simpler.
When an object is imaged in the later stage, the object can be located at any position of a displacement curve, and the position closer to the waist position is usually selected in consideration of imaging performance. After the relative position of the grating (including the beam splitting grating and the analysis grating) is fixed at a selected position, acquiring a circle of object image to complete phase contrast imaging; as shown in fig. 2, a background image acquisition of 9-step phase stepping is completed;
step 2, calculating the characteristic physical quantity of the background displacement curve in the step 1;
the characteristic physical quantities include: average light intensity, visibility, and initial phase;
the forward and backward projection method needs to calculate the slope of the waist position of each pixel displacement curve, involves fitting and differential calculation, and not only has large calculation amount, but also has low calculation precision. The method provided by the disclosure calculates the characteristic physical quantity of the background displacement curve by a traditional Fourier analysis method without calculating the slope of the displacement curve. The process can be used for parallel calculation, so that the calculation process is simplified, and the calculation speed is increased.
When the background image is expressed by a cosine function:
Figure BDA0002018401640000071
wherein L isb(x, y) is the gray value of the image collected by the detector, a (x, y) is the average light intensity of the background displacement curve, V0(x, y) is the visibility of the background displacement curve, xgFor relative displacement of gratings, p2In order to analyze the period of the grating,
Figure BDA0002018401640000072
the initial phase of the background displacement curve. And acquiring a background image in the experimental process, and calculating three characteristic physical quantities of average light intensity, visibility and an initial phase according to the background image.
Let Ibn(x, y) is the background image collected in the nth step, wherein N is more than or equal to 1 and less than or equal to N, N is more than or equal to 3, and N is the total number of steps, then the relative displacement x of the gratingg＝np2N, the three characteristic physical quantities can be respectively calculated by the following formulas:
Figure BDA0002018401640000073
Figure BDA0002018401640000074
Figure BDA0002018401640000075
wherein the function arg is the argument, and fig. 3A-3C are schematic diagrams of three characteristic quantities;
step 3, selecting an optimized step according to the characteristic physical quantity of the background displacement curve calculated in the step 2, and acquiring a forward image and a reverse image of the object based on the optimized step
Optimally selecting a suitable step position according to the initial phase calculated in step 2, such as the initial phase shown in fig. 3C (
Figure BDA0002018401640000081
Time) collecting object images, in the embodiment, the 3 rd step position is selected to finish the collection of the positive and negative object images, which are respectively shown in fig. 4A and 4B;
and 4, finishing X-ray phase contrast imaging according to the forward image, the reverse image, the optimized step and the characteristic physical quantity in the step 3.
The method provided by the disclosure is based on a displacement curve cosine function model, and can further obtain the phase and absorption information of an object by utilizing three characteristic physical quantities of each pixel background displacement curve, a selected stepping position and the positive and negative images of the object represented by the following two formulas;
Figure BDA0002018401640000082
Figure BDA0002018401640000083
wherein Is(x，y，φ)、Is(-x, y, phi + pi) are positive and negative images of the object respectively, M (x, y, phi) and theta (x, y, phi) are absorption and refraction signals of the object respectively,
Figure BDA0002018401640000084
in order to optimize the relative displacement of the stepping position grating, d is the distance between the beam splitting grating and the analysis grating.
We define F as the ratio of the forward and backward image projections, i.e.
Figure BDA0002018401640000085
And
Figure BDA0002018401640000086
Figure BDA0002018401640000087
where A (x, y) and B (x, y) are defined as the object imaging step amplitude cosine and sine quantities, respectively.
The following information extraction formula can be derived:
when a (x, y) -FA (-x, y) ≠ 0 and B (x, y) + FB (-x, y) ≠ 0
Figure BDA0002018401640000088
Figure BDA0002018401640000089
Wherein:
Figure BDA0002018401640000091
Figure BDA0002018401640000092
wherein C (x, y) is the forward projection light intensity of the step added object refraction signal of the object imaging, and D (x, y) is the back projection light intensity of the step added object refraction signal of the object imaging.
When A (x, y) -FA (-x, y) ≠ 0,
Figure BDA0002018401640000093
wherein the angle gamma0And beta0Is composed of
Figure BDA0002018401640000094
Figure BDA0002018401640000095
And (3) substituting the collected forward and reverse object images, the optimized stepping position and the three characteristic physical quantities calculated in the step (3) into formulas (7) - (13) to finish the extraction of the phase information and the absorption information of the X-ray phase contrast imaging method, thereby finishing the X-ray phase contrast imaging method.
As shown in fig. 4C to 4E, in order to verify the correctness of the present embodiment, 9-step phase-stepping object images were acquired, a refraction image of the object obtained by the phase stepping method as a comparative example is shown in fig. 4C, and a refraction image obtained by the present embodiment is shown in fig. 4D. And comparing the results obtained by the two methods, as shown in fig. 4E, the results obtained by the two methods have high goodness of fit.
So far, the embodiments of the present disclosure have been described in detail with reference to the accompanying drawings. It is to be noted that, in the attached drawings or in the description, the implementation modes not shown or described are all the modes known by the ordinary skilled person in the field of technology, and are not described in detail. Further, the above definitions of the various elements and methods are not limited to the various specific structures, shapes or arrangements of parts mentioned in the examples, which may be easily modified or substituted by those of ordinary skill in the art.
From the above description, those skilled in the art should clearly recognize that an X-ray phase contrast imaging method is proposed by the present disclosure.
In summary, the present disclosure provides an X-ray phase contrast imaging method, which calculates characteristic physical quantities of a background displacement curve of each pixel through point-by-point analysis, inherits the fast low-dose characteristics of a forward and backward projection method, reduces the requirements on the uniformity of a grating, and completes fast low-dose imaging under the condition that the phases of the displacement curves are not synchronous, thereby realizing large-field imaging.
It should also be noted that directional terms, such as "upper", "lower", "front", "rear", "left", "right", and the like, used in the embodiments are only directions referring to the drawings, and are not intended to limit the scope of the present disclosure. Throughout the drawings, like elements are represented by like or similar reference numerals. Conventional structures or constructions will be omitted when they may obscure the understanding of the present disclosure.
And the shapes and sizes of the respective components in the drawings do not reflect actual sizes and proportions, but merely illustrate the contents of the embodiments of the present disclosure. Furthermore, in the claims, any reference signs placed between parentheses shall not be construed as limiting the claim.
Furthermore, the word "comprising" does not exclude the presence of elements or steps not listed in a claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements.
The use of ordinal numbers such as "first," "second," "third," etc., in the specification and claims to modify a corresponding element does not by itself connote any ordinal number of the element or any ordering of one element from another or the order of manufacture, and the use of the ordinal numbers is only used to distinguish one element having a certain name from another element having a same name.
In addition, unless steps are specifically described or must occur in sequence, the order of the steps is not limited to that listed above and may be changed or rearranged as desired by the desired design. The embodiments described above may be mixed and matched with each other or with other embodiments based on design and reliability considerations, i.e., technical features in different embodiments may be freely combined to form further embodiments.
Those skilled in the art will appreciate that the modules in the device in an embodiment may be adaptively changed and disposed in one or more devices different from the embodiment. The modules or units or components of the embodiments may be combined into one module or unit or component, and furthermore they may be divided into a plurality of sub-modules or sub-units or sub-components. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and all of the processes or elements of any method or apparatus so disclosed, may be combined in any combination, except combinations where at least some of such features and/or processes or elements are mutually exclusive. Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Also in the unit claims enumerating several means, several of these means may be embodied by one and the same item of hardware.
Similarly, it should be appreciated that in the foregoing description of exemplary embodiments of the disclosure, various features of the disclosure are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various disclosed aspects. However, the disclosed method should not be interpreted as reflecting an intention that: that is, the claimed disclosure requires more features than are expressly recited in each claim. Rather, as the following claims reflect, disclosed aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the claims following the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of this disclosure.
The above-mentioned embodiments are intended to illustrate the objects, aspects and advantages of the present disclosure in further detail, and it should be understood that the above-mentioned embodiments are only illustrative of the present disclosure and are not intended to limit the present disclosure, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present disclosure should be included in the scope of the present disclosure.

Claims (6)

1. An X-ray phase contrast imaging method, comprising:
step 1, collecting a background image and forming a background displacement curve;
step 2, calculating the characteristic physical quantity of the background displacement curve in the step 1;
step 3, selecting an optimized step according to the characteristic physical quantity of the background displacement curve calculated in the step 2, and acquiring a forward image and a reverse image of the object based on the optimized step; and
step 4, finishing X-ray phase contrast imaging according to the forward image and the reverse image, the optimized step and the characteristic physical quantity in the step 3;
wherein the characteristic physical quantity includes: average light intensity, visibility, and initial phase;
the background image is represented as:
Figure FDA0002643244960000011
wherein Ib(x, y) is the gray value of the image collected by the detector, a (x, y) is the average light intensity of the background displacement curve, V0(x, y) is the visibility of the background displacement curve, xgFor relative displacement of gratings, p2In order to analyze the period of the grating,
Figure FDA0002643244960000012
the initial phase of the background displacement curve;
the average light intensity is:
Figure FDA0002643244960000013
wherein Ibn(x, y) is the background image acquired in the nth step, N is more than or equal to 1 and less than or equal to N, N is more than or equal to 3, and N is the total number of steps;
the visibility is as follows:
Figure FDA0002643244960000014
the initial phase is:
Figure FDA0002643244960000015
wherein the function arg is the argument.
2. The X-ray phase contrast imaging method of claim 1, wherein said acquiring a background image comprises:
under the condition of not placing an object, controlling the grating to step at equal intervals in the direction vertical to the grating line of the grating, and acquiring a background image when the grating steps one step; the stepping number of the grating is more than or equal to 3.
3. The X-ray phase contrast imaging method according to claim 1, wherein the characteristic physical quantity of the background displacement curve is calculated using a fourier analysis method.
4. The X-ray phase contrast imaging method of claim 1, wherein the forward and backward images of the object are:
Figure FDA0002643244960000021
Figure FDA0002643244960000022
wherein Is(x, y, phi) is a forward image of the object, Is(-x, y, phi + pi) is the reverse image of the object, M (x, y, phi) and theta (x, y, phi) are the absorption signal and the refraction signal of the object respectively,
Figure FDA0002643244960000023
d is the distance between the beam splitting grating and the analysis grating for optimized stepping position grating relative displacement.
5. An X-ray phase contrast imaging method according to claim 4, wherein the ratio of the projections of the forward image and the backward image is F, i.e. F
Figure FDA0002643244960000024
And
Figure FDA0002643244960000025
Figure FDA0002643244960000026
where A (x, y) and B (x, y) are defined as the object imaging step amplitude cosine and sine quantities, respectively.
6. The X-ray phase contrast imaging method according to claim 5, wherein when A (X, y) -FA (-X, y) ═ 0 and B (X, y) + FB (-X, y) ≠ 0
Figure FDA0002643244960000031
Figure FDA0002643244960000032
Wherein:
Figure FDA0002643244960000033
Figure FDA0002643244960000034
c (x, y) is the forward projection light intensity of the object imaging step added to the object refraction signal, and D (x, y) is the back projection light intensity of the object imaging step added to the object refraction signal;
when A (x, y) -FA (-x, y) ≠ 0,
Figure FDA0002643244960000035
wherein the angle gamma0And beta0Comprises the following steps:
Figure FDA0002643244960000036
Figure FDA0002643244960000037
CN201910274368.XA 2019-04-04 2019-04-04 X-ray phase contrast imaging method Active CN110133010B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201910274368.XA CN110133010B (en) 2019-04-04 2019-04-04 X-ray phase contrast imaging method

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201910274368.XA CN110133010B (en) 2019-04-04 2019-04-04 X-ray phase contrast imaging method

Publications (2)

Publication Number Publication Date
CN110133010A CN110133010A (en) 2019-08-16
CN110133010B true CN110133010B (en) 2020-10-27

Family

ID=67569325

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201910274368.XA Active CN110133010B (en) 2019-04-04 2019-04-04 X-ray phase contrast imaging method

Country Status (1)

Country Link
CN (1) CN110133010B (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111595877B (en) * 2020-05-27 2022-03-29 合肥工业大学 Multi-contrast image extraction method for X-ray diffraction enhanced imaging

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101467889A (en) * 2007-12-26 2009-07-01 中国科学院高能物理研究所 Grating shearing phase contrast CT image-forming data acquisition and reconstruction method
CN103356207A (en) * 2012-04-01 2013-10-23 中国科学院高能物理研究所 Medical test equipment and method based on grating shearing imaging

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9494534B2 (en) * 2012-12-21 2016-11-15 Carestream Health, Inc. Material differentiation with phase contrast imaging
CN105675631A (en) * 2016-01-05 2016-06-15 合肥泰禾光电科技股份有限公司 Fast fan-beam geometric phase contrast CT imaging device and method
US10859517B2 (en) * 2016-04-18 2020-12-08 The Board Of Trustees Of The Leland Stanford Junior University Single X-ray grating X-ray differential phase contrast imaging system

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101467889A (en) * 2007-12-26 2009-07-01 中国科学院高能物理研究所 Grating shearing phase contrast CT image-forming data acquisition and reconstruction method
CN103356207A (en) * 2012-04-01 2013-10-23 中国科学院高能物理研究所 Medical test equipment and method based on grating shearing imaging

Also Published As

Publication number Publication date
CN110133010A (en) 2019-08-16

Similar Documents

Publication Publication Date Title
CN104132953B (en) A kind of dual-energy x-ray phase contrast imaging device and its implementation
Willner et al. Quantitative X-ray phase-contrast computed tomography at 82 keV
CN101772324B (en) X-ray ct device
US7286640B2 (en) Dual-band detector system for x-ray imaging of biological samples
CN104394770B (en) Differential phase comparison imaging based on grating
WO2016070739A1 (en) Multi-energy spectrum x-ray grating imaging system and imaging method
Diemoz et al. Single-shot x-ray phase-contrast computed tomography with nonmicrofocal laboratory sources
JP5343065B2 (en) Radiography system
Lang et al. Experimental comparison of grating-and propagation-based hard X-ray phase tomography of soft tissue
JP2012085995A (en) Radiation imaging system
CN107847199B (en) Scanning X-ray device with full field-of-view detector
Sauter et al. Optimization of tube voltage in X-ray dark-field chest radiography
JP2012115576A (en) Radiological image detection apparatus, radiographic apparatus and radiographic system
CN103575750A (en) Arrangement and method for inverse X-ray phase contrast imaging
Kageyama et al. X-ray phase-imaging scanner with tiled bent gratings for large-field-of-view nondestructive testing
Wu et al. Prototype system of noninterferometric phase-contrast computed tomography utilizing medical imaging components
Donath et al. Phase-contrast imaging and tomography at 60 keV using a conventional x-ray tube source
Zamir et al. Recent advances in edge illumination x-ray phase-contrast tomography
Arboleda et al. Tilted-grating approach for scanning-mode X-ray phase contrast imaging
CN110133010B (en) X-ray phase contrast imaging method
CN110133011B (en) Stepping-free X-ray grating phase contrast imaging method
Beighley et al. 3D architecture of myocardial microcirculation in intact rat heart: a study with micro-CT
Da Silva et al. Optical calibration protocol for an x-ray and optical multimodality tomography system dedicated to small-animal examination
Liu et al. Optimization of reconstructed quality of hard x-ray phase microtomography
WO2020199194A1 (en) X-ray phase-contrast imaging method

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant