X-ray phase imaging with the unified modulated pattern analysis of near-field speckles at a laboratory source.

X-ray phase-contrast techniques are powerful methods for discerning features with similar densities, which are normally indistinguishable with conventional absorption contrast. While these techniques are well-established tools at large-scale synchrotron facilities, efforts have increasingly focused on implementations at laboratory sources for widespread use. X-ray speckle-based imaging is one of the phase-contrast techniques with high potential for translation to conventional x-ray systems. It yields phase-contrast, transmission, and dark-field images with high sensitivity using a relatively simple and cost-effective setup tolerant to divergent and polychromatic beams. Recently, we have introduced the unified modulated pattern analysis (UMPA) [Phys. Rev. Lett.118, 203903 (2017)PRLTAO0031-900710.1103/PhysRevLett.118.203903], which further simplifies the translation of x-ray speckle-based imaging to low-brilliance sources. Here, we present the proof-of-principle implementation of UMPA speckle-based imaging at a microfocus liquid-metal-jet x-ray laboratory source.

Trimodal low-dose X-ray tomography.

X-ray grating interferometry is a coherent imaging technique that bears tremendous potential for three-dimensional tomographic imaging of soft biological tissue and other specimens whose details exhibit very weak absorption contrast. It is intrinsically trimodal, delivering phase contrast, absorption contrast, and scattering ("dark-field") contrast. Recently reported acquisition strategies for grating-interferometric phase tomography constitute a major improvement of dose efficiency and speed. In particular, some of these techniques eliminate the need for scanning of one of the gratings ("phase stepping"). This advantage, however, comes at the cost of other limitations. These can be a loss in spatial resolution, or the inability to fully separate the three imaging modalities. In the present paper we report a data acquisition and processing method that optimizes dose efficiency but does not share the main limitations of other recently reported methods. Although our method still relies on phase stepping, it effectively uses only down to a single detector frame per projection angle and yields images corresponding to all three contrast modalities. In particular, this means that dark-field imaging remains accessible. The method is also compliant with data acquisition over an angular range of only 180° and with a continuous rotation of the specimen.

Speckle-based x-ray phase-contrast and dark-field imaging with a laboratory source.

We report on the observation and application of near-field speckles with a laboratory x-ray source. The detection of speckles is possible thanks to the enhanced brilliance properties of the used liquid-metal-jet source, and opens the way to a range of new applications in laboratory-based coherent x-ray imaging. Here, we use the speckle pattern for multimodal imaging of demonstrator objects. Moreover, we introduce algorithms for phase and dark-field imaging using speckle tracking, and we show that they yield superior results with respect to existing methods.

Three-dimensional imaging of whole mouse models: comparing nondestructive X-ray phase-contrast micro-CT with cryotome-based planar epi-illumination imaging.

In this study, we compare two evolving techniques for obtaining high-resolution 3D anatomical data of a mouse specimen. On the one hand, we investigate cryotome-based planar epi-illumination imaging (cryo-imaging). On the other hand, we examine X-ray phase-contrast micro-computed tomography (micro-CT) using synchrotron radiation. Cryo-imaging is a technique in which an electron multiplying charge coupled camera takes images of a cryo-frozen specimen during the sectioning process. Subsequent image alignment and virtual stacking result in volumetric data. X-ray phase-contrast imaging is based on the minute refraction of X-rays inside the specimen and features higher soft-tissue contrast than conventional, attenuation-based micro-CT. To explore the potential of both techniques for studying whole mouse disease models, one mouse specimen was imaged using both techniques. Obtained data are compared visually and quantitatively, specifically with regard to the visibility of fine anatomical details. Internal structure of the mouse specimen is visible in great detail with both techniques and the study shows in particular that soft-tissue contrast is strongly enhanced in the X-ray phase images compared to the attenuation-based images. This identifies phase-contrast micro-CT as a powerful tool for the study of small animal disease models.

A simplified approach for computed tomography with an X-ray grating interferometer.

We present a simplified acquisition and processing method for X-ray grating interferometry computed tomography (CT). The proposed approach eliminates the need to scan the gratings, thus allowing for a faster CT acquisition compared to methods presently in use. The contrast in the reconstructed images can be expressed as a linear combination of the absorption and refraction within the sample. Experimental images of a test phantom made of known materials and a human bone-cartilage sample prove the correctness of the method and show very good agreement with the theory. The here proposed approach might be highly interesting in many fields where a reduced imaging acquisition time is requested and/or where the radiation dose delivered to the sample has to be kept low, such as, for example, in in-vivo imaging.

Ptychographic X-ray nanotomography quantifies mineral distributions in human dentine.

Bones are bio-composites with biologically tunable mechanical properties, where a polymer matrix of nanofibrillar collagen is reinforced by apatite mineral crystals. Some bones, such as antler, form and change rapidly, while other bone tissues, such as human tooth dentine, develop slowly and maintain constant composition and architecture for entire lifetimes. When studying apatite mineral microarchitecture, mineral distributions or mineralization activity of bone-forming cells, representative samples of tissue are best studied at submicrometre resolution while minimizing sample-preparation damage. Here, we demonstrate the power of ptychographic X-ray tomography to map variations in the mineral content distribution in three dimensions and at the nanometre scale. Using this non-destructive method, we observe nanostructures surrounding hollow tracts that exist in human dentine forming dentinal tubules. We reveal unprecedented quantitative details of the ultrastructure clearly revealing the spatially varying mineralization density. Such information is essential for understanding a variety of natural and therapeutic effects for example in bone tissue healing and ageing.

Demonstration of Epstein-Barr viral genomes by in situ hybridization in acquired immune deficiency syndrome-related high grade and anaplastic large cell CD30+ lymphomas.

From September 1984 through December 1991, of those with human immunodeficiency virus infection seen at the acquired immune deficiency syndrome unit of the Centro di Riferimento Oncologico, Aviano, Italy, 71 patients had systemic non-Hodgkin's lymphomas. The most frequent histotypes were small noncleaved cell, anaplastic large cell (ALC) CD30/BerH2+, and large cell immunoblastic. In 22 representative cases of these histotypes, including 9 of small noncleaved cell, 9 of ALC CD30/BerH2+, and 4 of immunoblastic non-Hodgkin's lymphomas, Epstein-Barr virus genetic information was assessed by in situ hybridization and correlated with histologic and immunophenotypic findings. Expression of B-cell associated markers, usually including CD19, CD20, CD22, CDw75, and CD74, was found in 17 of the 22 evaluated cases. All small noncleaved cell and immunoblastic cases and four cases of ALC lymphomas expressed B-cell immunophenotypes, whereas the remaining ALC cases were immunologically undetermined. In situ hybridization detected Epstein-Barr virus in 12 of 22 cases (54.5%). Seven of nine ALC lymphomas were positive, as were three of five small noncleaved cell type (Burkitt's lymphoma), one of four small noncleaved cell type (non-Burkitt's variant), and one of four large cell immunoblastic type. The results of this study indicate that Epstein-Barr virus genomes might be identified in more than 50% of the evaluated high grade non-Hodgkin's lymphomas; this association occurred significantly more often in the small noncleaved cell lymphomas resembling endemic Burkitt's lymphoma (60%) and with ALC CD30/BerH2+ lymphomas (77.8%). These findings support the notion that Epstein-Barr virus may play a role in the development of non-Hodgkin's lymphomas in a proportion of human immunodeficiency virus-infected patients.

KP1/CD68 expression in malignant neoplasms including lymphomas, sarcomas, and carcinomas.

Expression of KP1/CD68 macrophage-associated antigen in a series of 840 selected malignant neoplasms, including immunomorphologically characterized cases of non-Hodgkin's lymphoma (NHL) (434), Hodgkin's disease (HD) (115), soft tissue sarcoma (147), carcinoma (49), and other tumors (95), was examined. KP1 expression was detected in a significant number of NHLs (107 of 434; 24.7%), most of them (65 of 107; 60.7%) of the diffuse small cell subtype. Only 14 of the 155 large cell lymphomas, compared to 10 of the 51 Ki-1/CD30+ anaplastic large cell (ALC) lymphomas examined, were KP1 positive. Conversely, none of the T-lineage NHL--other than Ki-1/CD30+ ALC lymphomas--or the HD cases tested was labeled by KP1 antibody. Among the other neoplasms tested, KP1 was reactive with a variable proportion of cases of malignant fibrous histiocytoma (19 of 24; 79.2%), malignant schwannoma (8 of 22; 36.4%), liposarcoma (3 of 9; 33.3%), leiomyosarcoma (8 of 37; 21.6%), cutaneous or metastatic melanoma (51 of 73; 69.9%), and renal cell carcinoma (3 of 5; 60%). These results indicate that KP1 shows a relatively wide spectrum of immunoreactivity with malignant neoplasms of presumed non-histiocyte origin, thus arguing against its expected specificity and high value in diagnostic pathology. Although the significance of KP1 expression by some subsets of NHLs remains to be elucidated, its close association with B-cell NHLs, mostly of the diffuse small cell type, should stimulate further pathologic and clinical investigations.

Quantitative electron density characterization of soft tissue substitute plastic materials using grating-based x-ray phase-contrast imaging.

Many scientific research areas rely on accurate electron density characterization of various materials. For instance in X-ray optics and radiation therapy, there is a need for a fast and reliable technique to quantitatively characterize samples for electron density. We present how a precise measurement of electron density can be performed using an X-ray phase-contrast grating interferometer in a radiographic mode of a homogenous sample in a controlled geometry. A batch of various plastic materials was characterized quantitatively and compared with calculated results. We found that the measured electron densities closely match theoretical values. The technique yields comparable results between a monochromatic and a polychromatic X-ray source. Measured electron densities can be further used to design dedicated X-ray phase contrast phantoms and the additional information on small angle scattering should be taken into account in order to exclude unsuitable materials.

Quantitative breast tissue characterization using grating-based x-ray phase-contrast imaging.

X-ray phase-contrast imaging has received growing interest in recent years due to its high capability in visualizing soft tissue. Breast imaging became the focus of particular attention as it is considered the most promising candidate for a first clinical application of this contrast modality. In this study, we investigate quantitative breast tissue characterization using grating-based phase-contrast computed tomography (CT) at conventional polychromatic x-ray sources. Different breast specimens have been scanned at a laboratory phase-contrast imaging setup and were correlated to histopathology. Ascertained tumor types include phylloides tumor, fibroadenoma and infiltrating lobular carcinoma. Identified tissue types comprising adipose, fibroglandular and tumor tissue have been analyzed in terms of phase-contrast Hounsfield units and are compared to high-quality, high-resolution data obtained with monochromatic synchrotron radiation, as well as calculated values based on tabulated tissue properties. The results give a good impression of the method's prospects and limitations for potential tumor detection and the associated demands on such a phase-contrast breast CT system. Furthermore, the evaluated quantitative tissue values serve as a reference for simulations and the design of dedicated phantoms for phase-contrast mammography.

Co-expression of Epstein-Barr virus latent membrane protein and vimentin in "aggressive" histological subtypes of Hodgkin's disease.

The presence of Epstein-Barr virus (EBV) genome in Hodgkin's and Reed-Sternberg (HRS) cells, as detected using in situ hybridization (ISH) with biotinylated BamHI "V" probes, along with the expression of EBV-encoded latent membrane protein (LMP) and vimentin was examined in paraffin-embedded sections of 39 immunomorphologically characterized cases of Hodgkin's disease (HD). ISH demonstrated EBV in HRS cells in 15 of 39 cases, whereas LMP expression was detected in 11 of 39 cases, only in the presence of EBV genome detection. With the exception of 1 case, in which HRS cells expressed B-cell-associated antigens, the LMP-positive cases included specimens in which HRS cells were of non-B, non-T phenotype. LMP expression showed a stronger association with lymphocyte depletion (LD) (3/3) and mixed cellularity (MC) (6/11) than with lymphocyte predominance (0/5) or nodular sclerosis (2/20) subtypes. Vimentin expression on HRS cells was found in all the LMP-expressing cases and only in a fraction (13/28) of LMP-negative cases. This study supports the view that HD represents a heterogeneous group of diseases also in terms of EBV association, LMP expression being strongly related to the "aggressive" LD and MC histological subtypes. In light of the supposed interactions between vimentin and LMP, their co-expression on HRS cells, as detected in this study, provides further evidence for a significant role of EBV in the development of a proportion of HD cases.