Realistic waveoptics simulation of x ray phase contrast imaging at a human scale yongjinsung1, w. Stability estimates for linearized nearfield phase retrieval in xray phase contrast imaging simon maretzkeyand thorsten hohagez abstract. Improved reconstruction technique for moire imaging using. X ray phase contrast imaging is a technique that aims to. Hertz biomedical and xray physics, royal institute of technology. Antiscatter grid is placed directly on the film screenfilmsystem detector geometrical limitation of radiation aperture antiscatter grid ideal. In the process, an x ray detector converts phase variations into intensity variations as the beams pass through a subject. Letters phase retrieval and differential phasecontrast imaging with lowbrilliance xray sources franz pfeiffer1, timm weitkamp2, oliver bunk1 and christian david 1 1paul scherrer institut, 5232 v illigen psi, switzerland 2forschungszentrum karlsruhe, 76021 karlsruhe, germany email. Applications of freespace propagation x ray phase contrast imaging are vast and definitely too many to be covered here. Besides covering fundamental concepts in both theory and practice, we also give opinions on future trends in x ray phase contrast imaging including x ray tomography, and comparison of di erent phase contrast imaging. 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.
Stability estimates for linearized nearfield phase retrieval in x ray phase contrast imaging simon maretzkeyand thorsten hohagez abstract. Pdf on the origin of speckle in xray phase contrast. Theoretical foundation and design considerations of a clinical feasible x. Propagationbased x ray phase contrast enables nanoscale imaging of biological tissue by probing not only the attenuation, but also the real part of the refractive index of the sample. Oct 26, 2018 to overcome the limited soft tissue contrast in conventional absorptionbased imaging, several new x ray phase contrast imaging methods have been developed 1. Imaging and detectors for medical physics lecture 3. The performance of a talbotlau interferometer depends to a great extent on its visibility.
Phase contrast x ray imaging could identify tumors earlier. Image reconstruction in quantitative xray phasecontrast. These ideas are applied to twodimensional and threedimensional propagationbased phase contrast imaging using. We demonstrate the applicability of propagationbased xray phasecontrast imaging at a laserassisted compact light source with known phantoms and the lungs and airways of a. Since phase contrast x ray imaging is not intrinsically coupled to the attenuation of x rays in tissues, but rather the refraction, the radiation dose may potentially be reduced by using for instance higher energy x rays than commonly used for attenuation contrast. Different from the analysis of imaging phase object with w. This means, to obtain high quality phasecontrast and darkfield images a high visibility is mandatory. Realistic waveoptics simulation of xray phasecontrast imaging at a human scale yongjinsung1, w.
The recent advances are going beyond microradiology and. Recently, a new mode of medical imaging known as xray phase contrast imaging xpci has been shown to produce exceptional contrast in soft tissues, and has the potential to noninvasively characterize atherosclerotic disease. Xray phasecontrast imaging employing multiple measurements chengying chou, yin huang, daxin shi, and mark a. Gratingbased talbotlau x ray interferometry is a novel imaging modality. Realistic waveoptics simulation of xray phasecontrast. Furthermore, there is some indication that these improvements of image quality can be maintained at reduced radiation doses. High resolution laboratory gratingbased xray phase.
Since phasecontrast xray imaging is not intrinsically coupled to the attenuation of xrays in tissues, but rather the refraction, the radiation dose may potentially be reduced by using for instance higher energy xrays than commonly used for attenuation contrast. Recent developments on x ray phase contrast imaging technology at csem. Liu a general theoretical formalism for xray phase contrast imaging where r e, n k, z k and f k are the classical electron radius, atomic density, atomic number and real part of the anomalous atomic scattering factor of the element k, respectively. Cloetens propagationbased phasecontrast imaging the forward problem. Gratingbased talbotlau xray interferometry is a novel imaging modality. It can be found in a variety of forms in diverse applications including metrology, precision measurements, alignment and imaging 11. Phasecontrast imaging depicts not only the absorption contrast but also the refraction contrast of the transmitted xray beam. Propagationbased xray phase contrast enables nanoscale imaging of biological tissue by probing not only the attenuation, but also the real part of the refractive index of the sample. 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. Phasecontrast xray imaging pci or phasesensitive 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. Propagationbased phasecontrast xray imaging at a compact. Designing the phase grating for talbotlau phasecontrast. Other xray imaging techniques xray fluoroscopy images are acquired continuously to study passage of xray contrast agent through gi tract. Xray 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.
Phase contrast xray imaging was first tested by snigirev et al. Biomedical xray phasecontrast imaging and tomography. Xray phasecontrast imaging is a technique that aims to. These ideas are applied to twodimensional and threedimensional propagationbased phasecontrast imaging using coherent xrays.
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. Pdf on the origin of speckle in xray phase contrast images of lung tissue marcus kitchen academia. Novel microstructured xray source designed for grating. X ray film layer raster absorber blade primary radiation scattered rad. At its current state, its medical use still has to be demonstrated. We will limit this discussion to few highlights like micro and nanotomography applications,,,, lung imaging,, and breast tissue imaging, including invivo. Recently, x ray phase contrast imaging has attracted a great deal of attention. Pci is particularly adapted to visualize weakly absorbing details like those often encountered in biology and medicine. Phasecontrast xray imaging in two and three dimensions. In the process, an xray detector converts phase variations into intensity variations as the beams pass through a subject. Tomographic reconstruction yields quantitative threedimensional maps of the xray refractive index, with a spatial resolution down to a few microns.
A general theoretical formalism for xray phase contrast. Phase contrast imaging, particularly of the breast, is being actively investigated. Development of phasecontrast xray imaging techniques and. Xray phase contrast imaging using standard equipment. The cone beam projects the selfimages of g 1 onto the plane of g 2 with a slightly magnified period p 1 14, resulting approximately in a combined phase oscillation of the form. In the last decade x ray imaging based on phase contrast greatly advanced thanks to the use of unmonochromatic synchrotron hard x rays. Phase contrast xray imaging 283 for soft tissues are computed tomography ct, magnetic resonance imaging mri, or ultrasound imaging 39. Phasecontrast xray imaging pci is an innovative method that is sensitive to the refraction of the xrays in matter. Mammography is the primary imaging tool for screening and diagnosis of human breast cancers, but. We consider the transportofintensity equation, as one particular method for xray phase contrast imaging among many, before passing on to the inverse problem of phase retrieval. Several parameters influence the visibility of such a system, like for example the x ray spectrum, the intergrating distances or the parameters of the three gratings. 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.
We demonstrate the applicability of propagationbased x ray phase contrast imaging at a laserassisted compact light source with known phantoms and the lungs and airways of a mouse. Recently, xray phase contrast imaging has attracted a great deal of attention. These images correspond to the electron density of the scanned specimen. Xray phasecontrast imaging and tomography make use of the refraction of xrays by the sample in image formation. Compared to standard absorption x ray imaging, it enables the acquisition of differential phase contrast images. 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. Xray phase tomography is an imaging technique that uses penetrating xrays to create volumetric views through slices or sections of soft biological tissues, such as tumors, and it offers.
Mar 29, 2017 please use one of the following formats to cite this article in your essay, paper or report. A codedaperture technique allowing xray phase contrast imaging with conventional sources. X ray phase contrast imaging adds the dimensions of bulk refractive index and wave scattering. Sandia national laboratories has developed an xray phase contrast imaging xpci technology that provides significantly improved imaging of.
Xray phase contrast imaging is a promising method for medical imaging and nondestructive testing. Phase retrieval and differential phasecontrast imaging. Us6804324b2 xray phase contrast imaging using a fabry. These tutorials introduce some basics of imaging with coherent x rays, focusing on phase contrast. Journal of xray science and technology 11 2003 3342 33 ios press a general theoretical formalism for xray phase contrast imaging xizeng wua and hong liub adepartment of radiology, university of alabama at birmingham, birmingham, al 35233, usa. To overcome the limited soft tissue contrast in conventional absorptionbased imaging, several new xray phasecontrast imaging methods have. Phasecontrast xray imaging could identify tumors earlier.
A general theoretical formalism for xray phase contrast imaging. 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. Information about the attenuation, smallangle scattering and phaseshifting properties of an object can be gained simultaneously in three image modalities using a talbotlau interferometer. 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. Osa xray phase contrast imaging of spherical capsules.
This book fills an important gap in the existing literature by providing a comprehensive discussion of xray phase contrast imaging xpci and its various uses and implementations. Atherton, targets for the national ignition campaign, j. Jul 24, 2003 theoretical foundation and design considerations of a clinical feasible x. Phase contrast imaging exploits differences in the refractive index of materials to differentiate and image them. Furthermore, socalled darkfield images are obtained. Line profiles and contrast to noise ratio values confirmed the superiority of phase contrast bt over conventional bt imaging. 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. This means, to obtain high quality phase contrast and darkfield images a high visibility is mandatory. Instead, the quantum electrodynamical treatment of phasecontrast imaging must be based on a different approach. Applications of freespace propagation xray phasecontrast imaging are vast and definitely too many to be covered here. Phase retrieval in xray phasecontrast imaging suitable for tomography anna burvall. Transparent phase masks, or phase gratings, imprint a periodic phase pattern on a wave front. Xray phasecontrast imaging is an important method for visualizing cellular and histological structures for a wide range of biological and medical studies.
Compared to standard absorption xray imaging, it enables the acquisition of differential phase contrast images. In the last decade xray imaging based on phase contrast greatly advanced thanks to the use of unmonochromatic synchrotron hard xrays. Conventional xray imaging measures the attenuation of x rays. Using a highefficiency grating interferometer for hard x rays 1030 kev and a phasestepping technique, separate radiographs of the phase and absorption profiles of bulk samples can be obtained from a single set of measurements. Fresnel diffraction coherence conditions the inverse problem phase retrieval methods holotomography recent developments projection microscopy kbbased imaging. Xray phasecontrast imaging is a promising method for medical imaging and nondestructive testing. This provides considerable additional information in the image compared to conventional xray imaging methods, which rely solely on xray absorption by the sample. 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. Yet, several early experimental results indicate that it has some potential for clinical applications. Recent developments on xray phase contrast imaging technology at csem.
Xray phase contrast imaging using a grating interferometer. In the context of biological and medical applications, a question is whether the refractive index is an independent contrast from attenuation. Imaging and detectors for medical physics dr barbara camanzi barbara. Novel microstructured xray source designed for gratingbased phase contrast imaging wenbing yun 1, sylvia lewis, david reynolds1, benjamin stripe 1, alan lyon, sharon chen 1, srivatsan seshadri 1, vladimir semenov, janos kirz. Highresolution, lowdose phase contrast xray tomography. Several parameters influence the visibility of such a system, like for example the xray spectrum, the intergrating distances or the parameters of the three gratings.
High resolution laboratory gratingbased xray phasecontrast. Phase retrieval in xray phasecontrast imaging suitable for. A universal moire effect and application in xray phase. Phasecontrast xray imaging virtually all xrays imaging in a medical or biological context is performed by measuring differences in the attenuation of xrays by the tissues. Exploring xray phase tomography with synchrotron radiation. Xpci could revolutionise all applications of x ray imaging. The material properties are inferred from the differences in the number of photons detected. The purpose of this work is to investigate the xray 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. This book fills an important gap in the existing literature by providing a comprehensive discussion of x ray phase contrast imaging xpci and its various uses and implementations. Xray phasecontrast imaging adds the dimensions of bulk refractive index and wave scattering. Concord, ca usa xray phase contrast imaging xpci is one of the most exciting new methods that has emerged. Phasecontrast xray imaging in two and three dimensions p. Recently, based on the talbot effect, groundbreaking work was reported using 1d gratings for xray phasecontrast imaging with a hospitalgrade xray tube.
Here we report a highresolution, lowdose phase contrast xray tomographic method for 3d diagnosis of human breast cancers. 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. Osa xray phase imaging with a grating interferometer. The material properties are inferred from the differences in the number of photons detected at the end of defined paths in the sample. Phase retrieval in xray phasecontrast imaging suitable. An intuitive explanation of the phase moire effect is illustrated in fig. We explain why the standard scattering treatment via fermis golden rule cannot be applied. Please use one of the following formats to cite this article in your essay, paper or report. Xray phase contrast imaging using a grating interferometer franz pfeiffer 1, timm weitkamp 2, and christian david 1 1 paul scherrer institut. X ray phase contrast imaging employing multiple measurements chengying chou, yin huang, daxin shi, and mark a. Phasecontrast imaging is a new xraybased technology that has been shown to provide enhanced softtissue contrast and improved visualization of cancerous structures.
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. It exploits a different mechanism to generate image. The pioneer method is the gratingbasedinterferometry which has no special requirements to the xray source and object size. Phase contrast imaging depicts not only the absorption contrast but also the refraction contrast of the transmitted x ray beam.
847 1098 437 1335 1063 827 57 468 520 504 1276 594 1222 792 1541 229 1503 371 159 93 1081 1545 613 278 121 399 398 1462 74 883 780 156 1033 1207 830