Modern X-ray Research Articles

Porous Media Characterization Using Minkowski Functionals: Theories, Applications and Future Directions

An elementary question in porous media research is in regard to the relationship between structure and function. In most fields, the porosity and permeability of porous media are properties of key interest. There is, however, no universal relationship between porosity and permeability since not only does the fraction of void space matter for permeability but also the connectivity of the void fraction. With the evolution of modern day X-ray microcomputed tomography (micro-CT) and advanced computing, it is now possible to visualize porous media at an unprecedented level of detail. Approaches in analyzing micro-CT data of porous structures vary in the literature from phenomenological characterization to network analysis to geometrical and/or topological measurements. This leads to a question about how to consistently characterize porous media in a way that facilitates theoretical developments. In this effort, the Minkowski functionals (MF) emerge from the field of statistical physics where it is evident that many physical processes depend on the geometry and topology of bodies or multiple bodies in 3D space. Herein we review the theoretical basis of the MF, mathematical theorems and methods necessary for porous media characterization, common measurement errors when using micro-CT data and recent findings relating the MF to macroscale porous media properties. This paper is written to provide the basics necessary for porous media characterization and theoretical developments. With the wealth of information generated from 3D imaging of porous media, it is necessary to develop an understanding of the limitations and opportunities in this exciting area of research.

Breast density as a risk factor of development of ductal carcinoma in situ

Objectives. to reveal a potential relationship between the breast density, various radiographic patterns of the breast structure, and the risk of developing ductal adenocarcinoma in situ.Methods.In this study, 169 patients were divided into 2 groups according to the modern X-ray classification L. Tabar. All patients underwent a core biopsy with subsequent histological examination. The first group consisted of 57 women (33.7%) with tumors arising in the terminal ductal-lobular unit – acinar adenocarcinoma (AAB) unifocal and multifocal forms, and the second group – 112 women (66.3%) with types of ductal adenocarcinoma in situ (in situ DAB) and ductal adenocarcinoma in situ associated with the acinar form of breast cancer (DAB + AAB). Pathologic findings on mammography were assessed using the modern classification of L. Tabar. Evaluation of the breast density was made using ACR 2013 classification. The Pattern of radiologic breast structure was evaluated according to the classification of L. Tabar.Results. According to our results, statistically significant differences of the compared groups on the breast density were established (p < 0.001). In the first group, patients with a density of ACR 1 prevailed, the proportion of which was 52.6%. In the second group, the incidence of ACR 4 was highest, with a share of 32.1% among all patients. Thus, it was concluded that there is an association of the breast density ACR 3 and ACR 4 and risk of development of DAB.Conclusions. The high breast density, as well as the IV and V type of the breast structure according to L. Tabar's classification, are statistically associated with an increased risk of developing ductal carcinoma in situ (DAB). Our study also showed a statistically significant difference in the age of onset of ductal and acinar adenocarcinoma of the breast – 52 and 64, respectively.

High-throughput micro-phenotyping measurements applied to assess stalk lodging in maize (Zea mays L.)

BackgroundThe biomechanical properties of maize stalks largely determine their lodging resistance, which affects crop yield per unit area. However, the quantitative and qualitative relationship between micro-phenotypes and the biomechanics of maize stalks is still under examined. In particular, the roles of the number, geometry, and distribution of vascular bundles of stalks in maize lodging resistance remain unclear. Research on these biomechanical properties will benefit from high-resolution micro-phenotypic image acquisition capabilities, which have been improved by modern X-ray imaging devices such as micro-CT and the development of micro-phenotyping analysis software. Hence, high-throughput image analysis and accurate quantification of anatomical phenotypes of stalks are necessary.ResultsWe have updated VesselParser version 1.0 to version 2.0 and have improved its performance, accuracy, and computation strategies. Anatomical characteristics of the second and third stalk internodes of the cultivars ‘Jingke968’ and ‘Jingdan38’ were analyzed using VesselParser 2.0. The relationships between lodging resistance and anatomical phenotypes of stalks between the two different maize varieties were investigated. The total area of vascular bundles in the peripheral layer, auxiliary axis diameter, and total area of vascular bundles were revealed to have the highest correlation with mechanical properties, and anatomical phenotypes of maize stalk were better predictors of mechanical properties than macro features observed optically from direct measurement, such as diameter and perimeter.ConclusionsThis study demonstrates the utility of VesselParser 2.0 in assessing stalk mechanical properties. The combination of anatomical phenotypes and mechanical behavior research provides unique insights into the problem of stalk lodging, showing that micro phenotypes of vascular bundles are good predictors of maize stalk mechanical properties that may be important indices for the evaluation and identification of the biomechanical properties to improve lodging resistance of future maize varieties.

Proton beam therapy for gastrointestinal cancers: past, present, and future.

Despite the conformality of modern X-ray therapy limiting high dose received by normal tissues the physical properties of X-rays make it impossible to avoid dose being delivered distal to the target. This "exit dose" is likely clinically significant especially for patients with gastrointestinal (GI) cancers when considering that even low dose received by the heart, lungs, bowel, and other radiosensitive structures can lead to morbidity and even may affect long-term tumor control. In contrast, proton beam therapy (PBT) delivers no "exit dose" and a growing body of literature suggests that this may improve clinical outcomes by reducing toxicity and even allowing for safe dose intensification to enhance tumor control. While there are not yet robust prospective data demonstrating the role of PBT for GI cancers, emerging retrospective data provide a strong rationale for continued study of how PBT may improve the therapeutic ratio for these patients. Here we review these data as well as discuss ongoing clinical trials of PBT for GI cancers.

Multidisciplinary approach in the treatment of cervical-cervical and cervical pregnancies with the use of modern low-invasive x-ray endovascular technology

Multidisciplinary approach in the treatment cervical ectopic pregnancy has been developed, it includes the systemic use of methotrexate, the embolization of uterine arteries and follow-up fetal egg remove. The new method of combination treatment of cervical pregnancy of one-stage use of embolization uterine artery and temporary balloon occlusion of the internal iliac arteries was applied for the first time in Russia. This algorithm helps to preserve the reproductive function of women.

APS Data Management System.

As the capabilities of modern X-ray detectors and acquisition technologies increase, so do the data rates and volumes produced at synchrotron beamlines. This brings into focus a number of challenges related to managing data at such facilities, including data transfer, near real-time data processing, automated processing pipelines, data storage, handling metadata and remote user access to data. The Advanced Photon Source Data Management System software is designed to help beamlines deal with these issues. This paper presents the system architecture and describes its components and functionality; the system's current usage is discussed, examples of its use have been provided and future development plans are outlined.

High-efficiency coherence-preserving harmonic rejection with crystal optics.

This work reports a harmonic-rejection scheme based on the combination of Si(111) monochromator and Si(220) harmonic-rejection crystal optics. This approach is of importance to a wide range of X-ray applications in all three major branches of modern X-ray science (scattering, spectroscopy, imaging) based at major facilities, and especially relevant to the capabilities offered by the new diffraction-limited storage rings. It was demonstrated both theoretically and experimentally that, when used with a synchrotron undulator source over a broad range of X-ray energies of interest, the harmonic-rejection crystals transmit the incident harmonic X-rays on the order of 10-6. Considering the flux ratio of fundamental and harmonic X-rays in the incident beam, this scheme achieves a total flux ratio of harmonic radiation to fundamental radiation on the order of 10-10. The spatial coherence of the undulator beam is preserved in the transmitted fundamental radiation while the harmonic radiation is suppressed, making this scheme suitable not only for current third-generation synchrotron sources but also for the new diffraction-limited storage rings where coherence preservation is an even higher priority. Compared with conventional harmonic-rejection mirrors, where coherence is poorly preserved and harmonic rejection is less effective, this scheme has the added advantage of lower cost and footprint. This approach has been successfully utilized at the ultra-small-angle X-ray scattering instrument at the Advanced Photon Source for scattering, imaging and coherent X-ray photon correlation spectroscopy experiments. With minor modification, the harmonic rejection can be improved by a further five orders of magnitude, enabling even more performance capabilities.

Measuring stress-induced martensite microstructures using far-field high-energy diffraction microscopy.

Modern X-ray diffraction techniques are now allowing researchers to collect long-desired experimental verification data sets that are in situ, three-dimensional, on the same length scales as critical microstructures, and using bulk samples. These techniques need to be adapted for advanced material systems that undergo combinations of phase transformation, twinning and plasticity. One particular challenge addressed in this article is direct analysis of martensite phases in far-field high-energy diffraction microscopy experiments. Specifically, an algorithmic forward model approach is presented to analyze phase transformation and twinning data sets of shape memory alloys. In the present implementation of the algorithm, the crystallographic theory of martensite (CTM) is used to predict possible martensite microstructures (i.e. martensite orientations, twin mode, habit plane, twin plane and twin phase fractions) that could form from the parent austenite structure. This approach is successfully demonstrated on three single- and near-single-crystal NiTi samples where the fundamental assumptions of the CTM are not upheld. That is, the samples have elastically strained lattices, inclusions, precipitates, subgrains, R-phase transformation and/or are not an infinite plate. The results indicate that the CTM still provides structural solutions that match the experiments. However, the widely accepted maximum work criterion for predicting which solution of the CTM should be preferred by the material does not work in these cases. Hence, a more accurate model that can simulate these additional structural complexities can be used within the algorithm in the future to improve its performance for non-ideal materials.

OA221] The dose to the lens of the eye for the heart team performing transcatheter aortic valve implementation (TAVI): Is there any concern for cataract?

Purpose To estimate and assess the lens doses to the heart team performing transcatheter aortic valve implementation (TAVI) from latest generation of interventional x-ray equipment and to establish correlations between the equivalent lens dose for each profession and the patient dose (dose-area product, DAP). Methods Thermoluminescence dosimeters (TLD) have been used to measure the lens dose without lead glasses, to the medical staff, in a cohort of 24 TAVI procedures. Detailed exam-specific dose-related data from radiation dose structured reports (RDSR) was used to analyze the components contributing to the operator’s eye lens dose. Results The mean annual dose (150 TAVI procedures) to the lens of the eye for the whole heart team (primary operator, secondary operator, anesthesiologist and the nurse) was 4.3 ± 1.5, 1.9 ± 0.68, 3.9 ± 1.4 and 1.1 ± 0.40 mSv. The mean DAP-value per procedure was 27 ± 19 Gycm2. The primary operator is exposed to the highest radiation dose with a conversion coefficient (equivalent dose to the lens/DAP) of 1.1 ± 0.27 μSv/Gycm2 of the left eye lens followed by the anesthesiologist, who was exposed for almost equally high lens doses but in both lenses, and the secondary operator with 0.48 ± 0.12 μSv/Gycm2 of the left eye lens. The nurse is located at a safe distance with the lowest conversion factor for the left eye lens (0.27 ± 0.069 μSv/Gycm2). Conclusions In modern interventional x-ray equipment, the TAVIs will contribute to radiation dose levels below the threshold value for cataract as long as a ceiling mounted shield is used. The information from the RDSR shows that the highest dose contribution to the primary operator’s lens is from the second half of the procedure due to the aortography section consisting of image acquisitions.

OA101] Assessment of dose efficiency of a modern X-ray fluoroscopy system using a model observer

Purpose The aim of this work was to measure image quality in terms of the square of the accumulation rate of the signal to noise ratio of low-contrast details, SNR rate 2 , kerma area product rate, P KA , rate and to quantify dose efficiency, SNR rate 2 / P KA , rate on a modern fluoroscopy system while varying the imaging conditions such as contrast detail size, X-ray beam size, dose rate, and object thickness. Methods The methodology derived by Tapiovaara et al. (Phys. Med. Biol., 38, 1761–1788, 1993, and STUK-A196, 2003) was used and implemented in MatlabTM. Measurement of model observer SNR rate 2 and P KA , rate were derived from stored fluoroscopy image sequences and the built-in kerma-area product reading on a Siemens Axiom Artis Zee MP system, respectively. 1024 image frames with and without the contrast detail were stored and subsequently analyzed by a model observer. SNR was calculated from the mean and standard deviation of the distributions of the decision variable. Finally, the long-term stability of the imaging system in terms of dose efficiency and the usefulness of the method as a quality control measure was evaluated. Results The precision in SNR rate 2 estimate was proportional to the inverse square root of the number of frames and SNR rate 2 was proportional to the area and squared thickness of the low-contrast detail. The dose efficiency increased with a factor of three with decreasing X-ray beam size from 242 cm2 to 182 cm2 and object thickness from 25 cm to 20 cm, hence quantifying the large dose efficiency gains by collimation and compression. The dose efficiency increased by 50% using the reduced dose rate compared to high dose rate. While the long-term stability of dose efficiency was measured with an uncertainty of ± 8%, the method is presently too time-consuming for routine quality control, mainly due to the slow data transfer of the large data files to the analysis server. Conclusions The results of the dose efficiency measurements under varying imaging conditions, agree with common radiological protection knowledge and allows changes in dose efficiency to be quantified which facilitate dose optimization in interventional procedures.

Particle acceleration at forward and reverse shocks in SNRs

Cosmic ray acceleration by astrophysical shocks in supernova remnants is briefly reviewed. Results of numerical modeling taking into account the magnetic field amplification by streaming instability and the shock modification are presented. Nonthermal emission produced by accelerated particles in old supernova remnants is compared with available data of modern radio, X-ray and gamma-ray astronomies. It is also shown that high-energy neutrinos produced in young supernova remnants of Type IIn extragalactic supernova can explain the recent IceCube detection of astrophysical neutrinos.

Modern technologies of X-ray systems for control of electronic components

Some issues of technology and design of modern X-ray devices for quality control of microelectronic devices are considered. The functional capabilities of both types of technologies are compared. The design of the Russian microfocus X-ray tube – a key element of the devices for control, is described.

Oxidative skeletal rearrangement of bicyclo[4.2.2]deca-2,4,7,9-tetraenes to bicyclo[4.3.1]deca-2,4,8-triene-7,10-diols and study of the antitumor activity of the products in vitro

Bicyclo[4.3.1]deca-2,4,8-triene-7,10-diols were synthesized in 76–85% yields by oxidative skeletal isomerization of the substituted bicyclo[4.2.2]deca-2,4,7,9-tetraenes of various structures on treatment with m-chloroperbenzoic acid. The structures of the obtained bicyclic unsaturated diols were reliably proven by modern spectral methods and X-ray diffraction. A high antitumor activity in vitro was found for bicyclo[4.3.1]deca-2,4,8-triene-7,10-diols against the Jurkat, K562, U937 and HL-60 tumor cell lines.

ESTIMATION OF ORGAN DOSES AND EFFECTIVE DOSES BASED ON IN-PHANTOM DOSIMETRY FOR INFANT DIAGNOSTIC CARDIAC CATHETERISATIONS WITH NOVEL X-RAY IMAGING TECHNOLOGY.

The present study evaluated the organ and effective doses in infant diagnostic cardiac catheterisation performed using a modern x-ray imaging unit by in-phantom dosimetry. In addition, conversion factors from dose-area product (DAP) to effective dose were determined. The organ and effective doses in 1-year old during diagnostic cardiac catheterisations were measured using radiophotoluminescence glass dosemeters implanted into an infant anthropomorphic phantom. The mean effective doses, evaluated according to the International Commission on Radiologic Protection Publication 103, were 4.0 mSv (range: 1.5-8.7 mSv). The conversion factors from DAP to effective dose were 2 and 3.5 mSv (Gy cm2)-1 for posteroanterior and lateral fluoroscopy, respectively, and 1.8 and 3.3 mSv (Gy cm2)-1 for posteroanterior and lateral cineangiography, respectively. The dose data and conversion factors evaluated in the present study may be useful for estimating radiation exposure in infants during diagnostic cardiac catheterisation.

Development and characterization of sub-monolayer coatings as novel calibration samples for X-ray spectroscopy

With the advent of both modern X-ray fluorescence (XRF) methods and improved analytical reliability requirements the demand for suitable reference samples has increased. Especially in nanotechnology with the very low areal mass depositions, quantification becomes considerably more difficult. However, the availability of suited reference samples is drastically lower than the demand. Physical vapor deposition techniques have been enhanced significantly in the last decade driven by the need for extremely precise film parameters in multilayer production. We have applied those techniques for the development of layer-like reference samples with mass depositions in the ng-range and well below for Ca, Cu, Pb, Mo, Pd, Pb, La, Fe and Ni. Numerous other elements would also be possible. Several types of reference samples were fabricated: multi-elemental layer and extremely low (sub-monolayer) samples for various applications in XRF and total-reflection XRF analysis. Those samples were characterized and compared at three different synchrotron radiation beamlines at the BESSY II electron storage ring employing the reference-free XRF approach based on physically calibrated instrumentation. In addition, the homogeneity of the multi-elemental coatings was checked at the P04 beamline at DESY. The measurements demonstrate the high precision achieved in the manufacturing process as well as the versatility of application fields for the presented reference samples.

On the Geometry of the X-Ray Emission from Pulsars. I. Model Formulation and Tests

X-ray pulsars are complex magnetized astronomical objects in which many different attributes shape the pulse profiles of the emitted radiation. For each pulsar, the orientation of the spin axis relative to our viewing angle, the inclination of the magnetic dipole axis relative to the spin axis, and the geometries of the emission regions all play key roles in producing its unique pulse profile. In this paper, we describe in detail a new geometric computer model for X-ray emitting pulsars and the tests that we carried out in order to ensure its proper operation. This model allows for simultaneous tuning of multiple parameters for each pulsar and, by fitting observed profiles, it has the potential to determine the underlying geometries of many pulsars whose pulse profiles have been cataloged and made public in modern X-ray databases.

Reconstruction of three-dimensional porous media using generative adversarial neural networks.

To evaluate the variability of multiphase flow properties of porous media at the pore scale, it is necessary to acquire a number of representative samples of the void-solid structure. While modern x-ray computer tomography has made it possible to extract three-dimensional images of the pore space, assessment of the variability in the inherent material properties is often experimentally not feasible. We present a method to reconstruct the solid-void structure of porous media by applying a generative neural network that allows an implicit description of the probability distribution represented by three-dimensional image data sets. We show, by using an adversarial learning approach for neural networks, that this method of unsupervised learning is able to generate representative samples of porous media that honor their statistics. We successfully compare measures of pore morphology, such as the Euler characteristic, two-point statistics, and directional single-phase permeability of synthetic realizations with the calculated properties of a bead pack, Berea sandstone, and Ketton limestone. Results show that generative adversarial networks can be used to reconstruct high-resolution three-dimensional images of porous media at different scales that are representative of the morphology of the images used to train the neural network. The fully convolutional nature of the trained neural network allows the generation of large samples while maintaining computational efficiency. Compared to classical stochastic methods of image reconstruction, the implicit representation of the learned data distribution can be stored and reused to generate multiple realizations of the pore structure very rapidly.

Predicting the X-ray polarization of type 2 Seyfert galaxies

Infrared, optical and ultraviolet spectropolarimetric observations have proven to be ideal tools for the study of the hidden nuclei of type-2 active galactic nuclei (AGN) and for constraining the composition and morphology of the sub-parsec scale emission components. In this paper, we extend the analysis to the polarization of the X-rays from type-2 AGN. Combining two radiative transfer codes, we performed the first simulations of photons originating in the gravity dominated vicinity of the black hole and scattering in structures all the way out to the parsec-scale torus and polar winds. We demonstrate that, when strong gravity effects are accounted for, the X-ray polarimetric signal of Seyfert-2s carries as much information about the central AGN components as spectropolarimetric observations of Seyfert-1s. The spectropolarimetric measurements can constrain the spin of the central supermassive black hole even in edge-on AGN, the hydrogen column density along the observer's line-of-sight, and the composition of the polar outflows. However, the polarization state of the continuum source is washed out by multiple scattering, and should not be measurable unless the initial polarization is exceptionally strong. Finally, we estimate that modern X-ray polarimeters, either based on the photo-electric effect or on Compton scattering, will require long observational times on the order of a couple of mega-seconds to be able to properly measure the polarization of type-2 AGN.

Application of Modern X-ray Spectroscopy in Chemistry—Beyond Studying the Oxidation State

Application of Modern X-ray Spectroscopy in Chemistry—Beyond Studying the Oxidation State

Polymer X-ray refractive nano-lenses fabricated by additive technology.

The present work demonstrates the potential applicability of additive manufacturing to X-Ray refractive nano-lenses. A compound refractive lens with a radius of 5 µm was produced by the two-photon polymerization induced lithography. It was successfully tested at the X-ray microfocus laboratory source and a focal spot of 5 μm was measured. An amorphous nature of polymer material combined with the potential of additive technologies may result in a significantly enhanced focusing performance compared to the best examples of modern X-ray compound refractive lenses.