Lowdose, simple, and fast gratingbased xray phase contrast imaging peiping zhua, kai zhanga, zhili wanga, yijin liua,b, xiaosong liua, ziyu wub,a,1, samuel a. Development of hard xray phasecontrast imaging csiropedia. X ray phase contrast imaging, which uses phase shift as the imaging signal, can provide remarkably improved contrast over conventional absorptionbased imaging for weakly absorbing samples, such as biological soft tissues and fibre composites. By extending the free space propagation between the sample and the detector up to 2 m, the xray wavefield diffracts and selfinterferes to.
Xray phase contrast imaging xpci has been the subject of intensive research in recent years. Improved reconstruction technique for moire imaging using. Xray phase contrast imaging using standard equipment. X ray phase contrast imaging is a promising method for medical imaging and nondestructive testing. Pdf towards the clinical application of xray phase. The three images in figure 1 are acquired simultaneously, and show two new imaging signals the differential phase contrast radiograph, based on refraction fig. Phasecontrast xray imaging virtually all x rays imaging in a medical or biological context is performed by measuring differences in the attenuation of x rays by the tissues. Early data suggest that this new modality may overcome some of the diagnostic limitations associated with current clinically available mammography systems and that it has potential for improving breast cancer detection. Talbotlau xray phase contrast setup for fast scanning of large samples. Pdf phase retrieval for xray inline phase contrast imaging. Csems xray phase contrast imaging xpci facility was extended in 2016 and now covers non destructive imaging from high resolution to high. Phase contrast pc arises because both the amplitude and phase of xrays are modi. Initial mammography studies confirming diagnostic benefits of the superior softtissue contrast of phase sensitive techniques were carried out with synchrotron radiation 4, 5. To bring xray phase contrast imaging to clinics and nondestructive testing workflows, a highly stable system with a.
Pdf phasecontrast xray imaging pci is an innovative method that is. To overcome the limited soft tissue contrast in conventional absorptionbased imaging, several new xray phase contrast imaging methods have. Tomographic images of a newborn piglet were obtained using a freespace propagation xray phasecontrast imaging setup at a synchrotron. Phasecontrast xray imaging in two and three dimensions. Recent developments on xray phase contrast imaging technology at csem.
May 15, 2014 phase contrast x ray imaging has enabled researchers to perform mammographic imaging that allows greater precision in the assessment of breast cancer and its precursors. Phase contrast imaging depicts not only the absorption contrast but also the refraction contrast of the transmitted xray beam. A novel approach for hard xray phase contrast imaging with a laboratory source is reported. Xray phasecontrast imaging with nanoradian angular. This article provides a quantitative characteriazation of an xray phase contrast imaging pci system based on the miniature synchrotron technology mirrorcle6x. At typical mammography xray energies of 1525 kev, the phase shift term can be up to times greater than the absorption termon the order of 107, compared to 10 10.
The purpose of this work is to investigate the x ray phase contrast properties of breast tissues and commonly used breast tissue substitutes or phantom materials with an aim of determining the phantom materials best representative of breast tissues. Phase contrast xray imaging 283 for soft tissues are computed tomography ct, magnetic resonance imaging mri, or ultrasound imaging 39. We will limit this discussion to few highlights like micro and nanotomography applications,,,, lung imaging,, and breast tissue imaging, including invivo. We then consider the role of partial coherence, and sketch a generic means by which partially coherent x.
Phase retrieval in xray phasecontrast imaging suitable for. The xray inline phase contrast system a consists only of the x. Phase contrast imaging is fundamentally a new xraybased imaging method that exploits the phase shift that occurs when xray waves pass through different components of a material. The material properties are inferred from the differences in the number of photons detected at the end of defined paths in the sample. Xray phasecontrast imaging is an important method for visualizing cellular and histological structures for a wide range of biological and medical studies. Phase contrast pc arises because both the amplitude and phase of x rays are modi. Some time later, a related letter to nature was submitted with the title phasecontrast imaging with polychromatic xrays and appeared in a november 1996 issue. Synchrotronbased propagationbased imaging, a type of phase contrast imaging, produces better soft tissue image contrast than conventional radiography. Sandia national laboratories has developed an xray phase contrast imaging xpci technology that provides significantly improved imaging of. Sep 01, 2018 the contrast expected from xray imaging can then be calculated as a function of xray energy. A codedaperture technique allowing xray phase contrast.
Medical differential phase contrast xray imaging dpci promises improved softtissue contrast at lower xray dose. Applications of free space propagation xray phasecontrast imaging are vast and definitely too many to be covered here. Talbot and talbotlau or grating interferometry 486 2. This work shows that propagationbased x ray phase contrast tomography, both at the synchrotron and even at a compact laboratory source, can be used to. Classical xray radiography is limited to measuring the attenuation experienced by radiation traversing the probed object. Sensitive phase gratings for xray phase contrast a. X ray phase contrast imaging pci is an emerging modality whose availability in clinics for mammography and lung imaging is expected to materialize within the coming years. Phase retrieval and differential phasecontrast imaging.
Fresnel diffraction coherence conditions the inverse problem phase retrieval methods holotomography recent developments projection microscopy kbbased imaging. Xray phase contrast imaging and tomography make use of the refraction of x rays by the sample in image formation. While traditional xray imaging yields an image that maps a samples absorptive properties by measuring xray photon flux from an xray source after it traverses a sample, xray phase. Phase contrast imaging is performed by directing radiation from a plurality of pinhole sources through a phase object to be imaged, wherein the phase object includes a first composition that produces a phase shift in the radiation relative to radiation passing through a second composition in the phase object and detecting a phase contrast image of the radiation after it passes through the. Up to now, it has been mostly limited to synchrotron radiation facilities, due to the stringent requirements on the xray source and detectors, and only one technique was shown to provide pci images. To determine whether the technique is directly transferable to the clinical environment for. Characterization of the phase contrast imaging system based. The material properties are inferred from the differences in the number of photons detected. X ray grating interferometry is promising to achieve this while keeping radiation dose and examination costs low.
Quantitative xray phasecontrast microtomography from a. Talbotlau xray phasecontrast setup for fast scanning of. Xray grating interferometry is promising to achieve this while keeping radiation dose and examination costs low. The sensitivity to the phase shift produced by the imaged object in addition to absorption leads to greatly increased contrast. Dec 11, 2019 x ray phase contrast imaging xpci is more sensitive to density variations than x ray absorption radiography, which is a crucial advantage when imaging weaklyabsorbing, lowz materials, or steep. The ability of phase contrast x ray imaging to depict blood vessels without contrast agents was tested by observing livers of a mouse and a rat with synchrotron x rays. This has been the underlying principle of xray imaging since. Jul 03, 2018 the complex cytoarchitecture of human brain tissue is traditionally studied by histology, providing structural information in 2d planes.
Knowledge of the basic physics, imaging sequences, and technical factors involved in phase contrast mri, specifically those for cardiac valvular flow imaging, cerebrospinal fluid flow analysis, angiography, fourdimensional blood flow imaging, and mr elastography, is essential for accurate image acquisition and interpretation. Phasecontrast xray imaging of breast article pdf available in acta radiologica 518. These ideas are applied to twodimensional and threedimensional propagationbased phase contrast imaging using coherent x rays. This method is of possible relevance in the field of diagnostic radiology. Motionless phase stepping in xray phase contrast imaging with a compact source.
Information about the attenuation, smallangle scattering and phase shifting properties of an object can be gained simultaneously in three image modalities using a talbotlau interferometer. The use of gratings as optical elements in hard x ray phase imaging overcomes some of the problems that have impaired the wider use of phase contrast in x ray radiography and tomography. Xray phasecontrast early detection of cancer and angiography applications are just two examples that can directly benefit from an imaging modality with excellent softtissue contrast. Oct 21, 2014 x ray phase tomography is an imaging technique that uses penetrating x rays to create volumetric views through slices or sections of soft biological tissues, such as tumors, and it offers. Gratingsbased phase contrast provides three physically distinct contrast mechanisms, which may improve material discrimination multiple measurement approaches exist, spanning a wide range of complexity, energy scalability, and texture length scales scatter contrast is based on ultrasmall angle xray elastic. Mcdonaldc,d, federica maronec, and marco stampanonic,e,1 ainstitute of high energy physics, chinese academy of sciences, beijing, 49, china. Improved reconstruction technique for moire imaging using an xray phasecontrast talbotlau interferometer. The xray phasecontrast techniques are innovative imaging methods allowing overtaking the limitations. Pdf motionless phase stepping in xray phase contrast. Applications of free space propagation xray phase contrast imaging are vast and definitely too many to be covered here. Phase contrast imaging pci solves the basic limitation of xray imaging, i. Phasecontrast computed tomography ct is an xraybased experimental imaging modality in which the phase shift of xrays passing through matter 2,3 rather than xray attenuation is used to generate tissue contrast. Standard x ray imaging techniques like radiography or computed tomography ct rely on a decrease.
Biomedical xray phasecontrast imaging and tomography. Phase contrast xray imaging is a powerful technique for the detection of low contrast details in weakly absorbing objects. Propagationbased phase contrast uses free space propagation to get edge enhancement, talbot and polychromatic farfield interferometry uses a set of diffraction gratings to measure the derivative of the phase, refractionenhanced imaging uses an analyzer crystal also for differential measurement, and xray interferometry uses a crystal. Phase contrast xray imaging 126 has been for almost 10 years a very active. Exploring xray phase tomography with synchrotron radiation. This has become a seminal work in the field of propagationbased xray phase contrast imaging with over 500 citations to the beginning of 2010.
Standard xray imaging techniques like radiography or computed tomography ct rely on a decrease of the xray beams intensity attenuation when. Phase contrast x ray imaging virtually all x rays imaging in a medical or biological context is performed by measuring differences in the attenuation of x rays by the tissues. Xray phasecontrast imaging adds the dimensions of bulk refractive index and wave scattering. Xray phase contrast imaging is a promising method for medical imaging and. Aug 03, 2010 phase sensitive x ray imaging methods can provide substantially increased contrast over conventional absorptionbased imaging and therefore new and otherwise inaccessible information. We explain why the standard scattering treatment via fermis golden rule cannot be applied. Xray phase contrast imaging is a promising method for medical imaging and nondestructive testing.
Free space propagation can also transform the phase modulation of the. The cxro website provides the necessary tools for doing this henke et al. The limitation of a single contrast mechanism in xray imaging has. Instead, the quantum electrodynamical treatment of phasecontrast imaging must be based on a different approach. Livers were excised by tying arteries and veins to prevent blood from flowing out of the liver. We consider image formation using the free space propagation of xrays from a point source passing. Pdf recent developments on xray phase contrast imaging. Contribution to phase contrast imaging, reconstruction and.
Feb 09, 2010 phased contrast x ray imaging, which uses silicon gratings to detect distortions in the x ray wave front, may be applicable to mail or luggage scanning for explosives. This provides considerable additional information in the image compared to conventional xray imaging methods, which rely solely on xray absorption by the sample. X ray phase contrast early detection of cancer and angiography applications are just two examples that can directly benefit from an imaging modality with excellent softtissue contrast. Phase contrast xray imaging pci or phase sensitive xray imaging is a general term for different technical methods that use information concerning changes in the phase of an xray beam that passes through an object in order to create its images.
Experimental research on the feature of an xray talbotlau. Realistic waveoptics simulation of x ray phase contrast imaging at a human scale yongjinsung1, w. Study of dynamic phase contrast x ray imaging of lungs indicates further that the phase contrast x ray imaging technique may identify and locate airway liquid and allows lung aeration in newborn rabbit pups to be dynamically visualized. Phasecontrast imaging can be implemented by freespace. Propagationbased phasecontrast xray imaging at a compact. Phase contrast imaging technology when x rays are used in medical imaging, the differences in density and atomic number of various components of an object result in different degrees of absorption of the x rays and are ultimately responsible for image formation and image contrast. Phase sensitive xray imaging methods show the potential to circumvent this problem by utilizing the intrinsically enhanced electron density contrast. In the past few years, xray phasecontrast and darkfield imaging have evolved to be invaluable tools for nondestructive sample visualisation, delivering. The problem of phase retrieval from intensity measurements currently attracts much attention in the area of xray phase contrast imaging, it is a quantitative technology to get the internal structure information of weakly absorbing object, and it has always been a subject of considerable interest in xray optics. Inline phase contrast x ray imaging provides images where both absorption and refraction contribute. As a result, a local phase shift will be generated in the xray wave after exiting the object. Phasecontrast imaging of weakly absorbing materials using hard xrays. Phase contrast imaging depicts not only the absorption contrast but also the refraction contrast of the transmitted x ray beam. X rays passing through regions of differing d pick up different.
Recent advances in synchrotronbased hard xray phase. The current implementation of the examined imaging system is a prototype of the socalled inline modality of the xray pci, which can, however, potentially be modi. Gratingsbased phase contrast imaging for explosives detection. X ray phase contrast imaging techniques either directly or indirectly sense wave refraction through mechanisms that convert it to an intensity signal. Realistic waveoptics simulation of xray phase contrast imaging at a human scale yongjinsung1, w. Mar 29, 2017 please use one of the following formats to cite this article in your essay, paper or report. Xray phase contrast imaging xpci refers to any xray based technique that renders phase variations visible through translating phase changes into intensity variations that can be recorded. Development of xray phasecontrast imaging techniques for. The notion of phase retrieval goes a step beyond phase. Xray radiographic absorption imaging is an invaluable tool in medical diagnostics and materials science.
For quantitative analysis of these images, the phase needs to be retrieved numerically. Development of phasecontrast xray imaging techniques and. Us6804324b2 xray phase contrast imaging using a fabry. Hertz biomedical and xray physics, royal institute of technology. Inline phasecontrast xray imaging and tomography for. Nov 17, 2018 sandia national laboratories has developed an x ray phase contrast imaging xpci technology that provides significantly improved imaging of low density materials for commercial and security. Imaging free fulltext state of the art of xray specklebased. Phase retrieval in xray phasecontrast imaging suitable for tomography anna burvall. Phased contrast xray imaging, which uses silicon gratings to detect distortions in the xray wave front, may be applicable to mail or luggage scanning for explosives. This is a highly sensitive approach for retrieving this information. Phase contrast x ray imaging could identify tumors earlier.
A phase retrieval algorithm for xray phase contrast. Due to the fact that the results have been obtained with a standard,relatively lowcost and commercially available xray tube generator,we envision a widespread application of our m ethod in areas where phase imaging would be desirable,but is. Phase contrast x ray imaging pci or phase sensitive x ray imaging is a general term for different technical methods that use information concerning changes in the phase of an x ray beam that passes through an object in order to create its images. The pioneer method is the gratingbasedinterferometry which has no special requirements to the xray source and object size. Recently, based on the talbot effect, groundbreaking work was reported using 1d gratings for x ray phase contrast imaging with a hospitalgrade x ray tube. Cloetens propagationbased phasecontrast imaging the forward problem. Phase contrast x ray imaging was first tested by snigirev et al.
Lowdose, simple, and fast gratingbased xray phasecontrast. A comparison of absorption and phase contrast for xray. Quantitative phase contrast imaging of a shockwave with a. X ray imaging is of paramount importance for clinical and preclinical imaging but it is fundamentally restricted by the attenuationbased contrast mechanism, which has remained essentially the same since roentgens discovery a century ago. Thus it may be possible to observe phase contrast when absorption contrast is undetectable. Xray darkfield imaging with a single absorption grating. High resolution laboratory gratingbased xray phase. Monte carlo simulation of xray inline phase contrast infrastructure for grid computing exist vip, gatelab, focus is for the moment on the physics problems. The dose strongly depends on both the angular sensitivity and on the visibility of a gratingbased talbotlau interferometer. W 1 is the first wavefront and w 2 is the second wavefront. The improvement with respect to conventional absorptionbased methods is apparent, and is particularly important. Phase contrast imaging, particularly of the breast, is being actively investigated.
Second, phase contrast imaging requires a microfocus xray source to give xray illumination with sufficient spatial coherence to show interference. The technique is based on total external reflection from the edge of a mirror, aligned to intercept. This can be partly extended to 3d by inspecting many parallel slices, however, at nonisotropic resolution. In the process, an x ray detector converts phase variations into intensity variations as the beams pass through a subject. Phasecontrast xray imaging in two and three dimensions p. Phasecontrast xray imaging could identify tumors earlier. Xray phase contrast imaging using a grating interferometer. Realistic waveoptics simulation of xray phasecontrast. Such sources typically have a low flux because of the small emission spot, and the exposure times using other microct systems than the one described in our study may therefore be much longer.
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