Instrument Design and Image Reconstruction For A Laboratory X-Ray Microtomograph

1990 ◽  
Vol 48 (1) ◽  
pp. 518-519
Author(s):  
Roger H. Johnson ◽  
Alan C. Nelson ◽  
David H. Burns
Keyword(s):  
Low Cost ◽  
Three Dimensional ◽  
Thin Foil ◽  
Cone Beam ◽  
X Rays ◽  
Two Dimensional ◽  
Rotating Shaft ◽  
Data Set ◽  
Solid State Detector ◽  
X Ray

X-ray microscopy has received considerable attention over the years, since it has the potential of producing high-resolution images of thick specimens in air. We are developing an x-ray microtomograph for three-dimensional imaging of small biological specimens. The instrument, shown in Figure 1, has much in common with projection x-ray microscopes of decades past, but incorporates several technological advances of recent years to partially overcome the limitations of the older instruments. The most important of these are the use of a planar solid-state detector and the provision for volume reconstruction. We describe the design for a relatively low-cost instrument intended for 3-D imaging of biological specimens up to ten cubic millimeters in size.The x-ray source for the microtomograph consists of a modified SEM. The electron beam, in spot mode and focused to about ten nanometers, impinges on a thin foil target to produce an emergent, low-intensity cone beam of characteristic and Bremsstrahlung x-rays. The foil resides in close proximity to an optional aluminum filter and a thin beryllium window which terminates the evacuated electron column. The specimen is mounted on a precision rotating shaft within two millimeters of the target foil. A two-dimensional detector is placed ten to forty centimeters from the sample, providing direct projection magnifications of up to 200 times. Two-dimensional projection views are collected at each of many angular orientations as the sample is rotated through 360 degrees. Cone beam backprojection algorithms are then applied to reconstruct a threedimensional data set.

SARS n-CoV2-19 detection from chest x-ray images using deep neural networks

2020 ◽  
Vol 16 (5) ◽  
pp. 419-427 ◽  
Author(s):  
Mohammad Khalid Pandit ◽  
Shoaib Amin Banday
Keyword(s):  
Health Care Professionals ◽  
Low Cost ◽  
Fine Tuning ◽  
Medical Community ◽  
X Rays ◽  
Data Set ◽  
Content Type ◽  
X Ray ◽  
Chest X Ray ◽  
Novel Coronavirus

Purpose Novel coronavirus is fast spreading pathogen worldwide and is threatening billions of lives. SARS n-CoV2 is known to affect the lungs of the COVID-19 positive patients. Chest x-rays are the most widely used imaging technique for clinical diagnosis due to fast imaging time and low cost. The purpose of this study is to use deep learning technique for automatic detection of COVID-19 using chest x-rays. Design/methodology/approach The authors used a data set containing confirmed COVID-19 positive, common bacterial pneumonia and healthy cases (no infection). A collection of 1,428 x-ray images is used in this study. The authors used a pre-trained VGG-16 model for the classification task. Transfer learning with fine-tuning was used in this study to effectively train the network on a relatively small chest x-ray data set. Initial experiments show that the model achieves promising results and can be greatly used to expedite COVID-19 detection. Findings The authors achieved an accuracy of 96% and 92.5% in two and three output class cases, respectively. Based on these findings, the medical community can access using x-ray images as possible diagnostic tool for faster COVID-19 detection to complement the already testing and diagnosis methods. Originality/value The proposed method can be used as initial screening which can help health-care professionals to better treat the COVID patients by timely detecting and screening the presence of disease.

scholarly journals BINoculars: data reduction and analysis software for two-dimensional detectors in surface X-ray diffraction

2015 ◽  
Vol 48 (4) ◽  
pp. 1324-1329 ◽  
Author(s):  
Sander Roobol ◽  
Willem Onderwaater ◽  
Jakub Drnec ◽  
Roberto Felici ◽  
Joost Frenken
Keyword(s):  
Data Reduction ◽  
Modular Design ◽  
Reciprocal Lattice ◽  
Measurement Techniques ◽  
Three Dimensional ◽  
Two Dimensional ◽  
X Ray Diffraction ◽  
Data Set ◽  
High Resolution Data ◽  
X Ray

BINocularsis a tool for data reduction and analysis of large sets of surface diffraction data that have been acquired with a two-dimensional X-ray detector. The intensity of each pixel of a two-dimensional detector is projected onto a three-dimensional grid in reciprocal-lattice coordinates using a binning algorithm. This allows for fast acquisition and processing of high-resolution data sets and results in a significant reduction of the size of the data set. The subsequent analysis then proceeds in reciprocal space. It has evolved from the specific needs of the ID03 beamline at the ESRF, but it has a modular design and can be easily adjusted and extended to work with data from other beamlines or from other measurement techniques. This paper covers the design and the underlying methods employed in this software package and explains howBINocularscan be used to improve the workflow of surface X-ray diffraction measurements and analysis.

Material analysis end-station of the Hyogo-ken beamline at SPring-8

1998 ◽  
Vol 5 (3) ◽  
pp. 509-511 ◽  
Author(s):  
T. Kaneyoshi ◽  
T. Ishihara ◽  
H. Yoshioka ◽  
M. Motoyama ◽  
S. Fukushima ◽  
...  
Keyword(s):  
Surface Analysis ◽  
Three Dimensional ◽  
Grazing Incidence ◽  
Incidence Geometry ◽  
X Rays ◽  
X Ray Diffraction ◽  
Solid State Detector ◽  
X Ray ◽  
Grazing Incidence Geometry ◽  
State Detector

Plans to construct surface-analysis equipment which will be placed on beamline BL24XU of SPring-8 are presented. There are three experimental hutches in BL24XU, which are available simultaneously by using diamond monochromators as beam splitters. The purpose of the surface-analysis equipment is the simultaneous measurement of fluorescent and diffracted X-rays in grazing-incidence geometry. The instrument is equipped with a solid-state detector (SSD) and a flat position-sensitive proportional counter (PSPC) combined with analysing crystals for X-ray fluorescence (XRF) analysis. A curved PSPC and the goniometer that mounts the SSD used for XRF are also installed for X-ray diffraction. X-ray fluorescence holography and polarized X-ray emission spectroscopy modes are available, so three-dimensional images of atomic configurations and also the anisotropic structure of materials will be studied.

scholarly journals Texture and Lamellae Distribution Functions in Lamellar Eutectics

1986 ◽  
Vol 6 (4) ◽  
pp. 265-287 ◽  
Author(s):  
H. J. Bunge
Keyword(s):  
Three Dimensional ◽  
Orientation Distribution ◽  
Distribution Functions ◽  
X Rays ◽  
Two Dimensional ◽  
Absorption Factor ◽  
X Ray Diffraction ◽  
Diffraction Vector ◽  
X Ray ◽  
Pole Figures

The crystallographic orientation distribution and the geometrical lamellae orientation distribution in lamellar eutectics are, in general, not independent of each other. The combined orientation-lamellae distribution function depends on five angular parameters. X-ray diffraction in such eutectics may exhibit an anisotropic macroscopic absorption factor if the penetration depth of the X-rays is large compared with their planar size. As a consequence, the reflected X-ray intensity may depend on a third angle γ, i.e. a rotation of the sample about the diffraction vector s additionally to the usual pole figure angles α, β which describe the orientation of the diffraction vector s with respect to the sample coordinate system. It is thus necessary to measure three-dimensional generalized pole figures instead of conventional two-dimensional ones.

The Role of Chemical Substances in Classic and Modern Sialography Technique and applications

2018 ◽  
Vol 68 (12) ◽  
pp. 2829-2831
Author(s):  
Danisia Haba ◽  
Cristian Budacu ◽  
Mihai Constantin ◽  
Victor Vlad Costan ◽  
Alexandru Nemtoi
Keyword(s):  
Three Dimensional ◽  
Cone Beam ◽  
Prospective Clinical Study ◽  
Two Dimensional ◽  
Chemical Substances ◽  
X Ray ◽  
Time Period ◽  
Plain Image ◽  
Oral And Maxillofacial Surgeon

The purpose of this study was to assess the role of a chemical contrast medium used in plain x ray and CBCT (cone beam computed tomography) sialography imaging in the detection of different changes associated with lesions of salivary glands. 20 subjects were recruited into this prospective clinical study over a 1 year time period. Sialography was performed by an oral and maxillofacial surgeon. A lateral skull plain image was then made and a three-dimensional scanning using a CBCT machine. The imaging volume was centred on the gland of interest. The lateral skull plain images represented the two-dimensional part of the study, and these were used for comparison with the three-dimensional investigation, the CBCT images.

The crystal and molecular structure of quaterrylene: a redetermination

1975 ◽  
Vol 344 (1637) ◽  
pp. 199-215 ◽  
Keyword(s):  
Molecular Structure ◽  
Crystal Structure ◽  
Crystal And Molecular Structure ◽  
Average Length ◽  
Three Dimensional ◽  
Interlayer Spacing ◽  
Two Dimensional ◽  
Data Set ◽  
X Ray ◽  
Total Data

The crystal structure of quaterrylene, C 40 H 20 -first studied with limited two dimensional X-ray data in 1960 - has been redetermined with three dimensional data. Some 2816 independent reflexions have been measured. Fullmatrix least-squares refinement with large matrices of up to 200 parameters has reduced Rto 4.00 % for the 1162 reflexions with intensities significantly above background and 11.04% for the total data set. Carbon atom positions were refined anisotropically and C-C distances have been determined with an estimated standard deviation of ±0.004 A. The average length of the six pen-bonds is 1.465(5) Å . These can be divided into two chemically equivalent sets with an average length of 1.467(3) Å for the four outer bonds and 1.462(6) Å for the central pair. The crystal contains dimers consisting of two centro-symmetrically related molecules separated by a mean perpendicular distance of 3.41 Å . This is smaller than the corresponding separation in a-perylene, and approaches the interlayer spacing in graphite. There are small, significant deviations from planarity in the quaterrylene molecule at least some of which seem to be related to the interactions between the two molecules of the dimer.

Influence of X-Ray Induced Fluorescence on Energy Dispersive X-Ray Analysis of Thin Foils

1977 ◽  
Vol 35 ◽  
pp. 328-329
Author(s):  
E. A. Kenik ◽  
J. Bentley
Keyword(s):  
Thin Foil ◽  
Electron Excitation ◽  
Simple Approach ◽  
Foil Thickness ◽  
X Rays ◽  
X Ray ◽  
Hole Spectrum ◽  
Illumination System ◽  
Thin Foils ◽  
Intensity Ratios

Cliff and Lorimer (1) have proposed a simple approach to thin foil x-ray analy sis based on the ratio of x-ray peak intensities. However, there are several experimental pitfalls which must be recognized in obtaining the desired x-ray intensities. Undesirable x-ray induced fluorescence of the specimen can result from various mechanisms and leads to x-ray intensities not characteristic of electron excitation and further results in incorrect intensity ratios.In measuring the x-ray intensity ratio for NiAl as a function of foil thickness, Zaluzec and Fraser (2) found the ratio was not constant for thicknesses where absorption could be neglected. They demonstrated that this effect originated from x-ray induced fluorescence by blocking the beam with lead foil. The primary x-rays arise in the illumination system and result in varying intensity ratios and a finite x-ray spectrum even when the specimen is not intercepting the electron beam, an ‘in-hole’ spectrum. We have developed a second technique for detecting x-ray induced fluorescence based on the magnitude of the ‘in-hole’ spectrum with different filament emission currents and condenser apertures.

scholarly journals Is Micro X-ray Computer Tomography a Suitable Non-Destructive Method for the Characterisation of Dental Materials?

Polymers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1271
Author(s):  
Andreas Koenig ◽  
Leonie Schmohl ◽  
Johannes Scheffler ◽  
Florian Fuchs ◽  
Michaela Schulz-Siegmund ◽  
...  
Keyword(s):  
Flexural Strength ◽  
Computer Tomography ◽  
Mechanical Performance ◽  
Dental Materials ◽  
Three Dimensional ◽  
X Rays ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Multiple Measurements ◽  
High Doses

The aim of the study was to investigate the effect of X-rays used in micro X-ray computer tomography (µXCT) on the mechanical performance and microstructure of a variety of dental materials. Standardised bending beams (2 × 2 × 25 mm3) were forwarded to irradiation with an industrial tomograph. Using three-dimensional datasets, the porosity of the materials was quantified and flexural strength was investigated prior to and after irradiation. The thermal properties of irradiated and unirradiated materials were analysed and compared by means of differential scanning calorimetry (DSC). Single µXCT measurements led to a significant decrease in flexural strength of polycarbonate with acrylnitril-butadien-styrol (PC-ABS). No significant influence in flexural strength was identified for resin-based composites (RBCs), poly(methyl methacrylate) (PMMA), and zinc phosphate cement (HAR) after a single irradiation by measurement. However, DSC results suggest that changes in the microstructure of PMMA are possible with increasing radiation doses (multiple measurements, longer measurements, higher output power from the X-ray tube). In summary, it must be assumed that X-ray radiation during µXCT measurement at high doses can lead to changes in the structure and properties of certain polymers.

Visualizing Fluid Flows With X-Rays

2007 ◽  
Author(s):  
Theodore J. Heindel ◽  
Terrence C. Jensen ◽  
Joseph N. Gray
Keyword(s):  
Computed Tomography ◽  
Flow Visualization ◽  
Three Dimensional ◽  
Fluid Flows ◽  
X Rays ◽  
Radiographic Images ◽  
Optical Access ◽  
X Ray ◽  
X Ray Computed ◽  
Density Map

There are several methods available to visualize fluid flows when one has optical access. However, when optical access is limited to near the boundaries or not available at all, alternative visualization methods are required. This paper will describe flow visualization using an X-ray system that is capable of digital X-ray radiography, digital X-ray stereography, and digital X-ray computed tomography (CT). The unique X-ray flow visualization facility will be briefly described, and then flow visualization of various systems will be shown. Radiographs provide a two-dimensional density map of a three dimensional process or object. Radiographic images of various multiphase flows will be presented. When two X-ray sources and detectors simultaneously acquire images of the same process or object from different orientations, stereographic imaging can be completed; this type of imaging will be demonstrated by trickling water through packed columns and by absorbing water in a porous medium. Finally, local time-averaged phase distributions can be determined from X-ray computed tomography (CT) imaging, and this will be shown by comparing CT images from two different gas-liquid sparged columns.

scholarly journals Study on X-ray Induced Two-Dimensional Thermal Shock Waves in Carbon/Phenolic

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3553
Author(s):  
Dengwang Wang ◽  
Yong Gao ◽  
Sheng Wang ◽  
Jie Wang ◽  
Haipeng Li
Keyword(s):  
Numerical Simulation ◽  
Shock Wave ◽  
Wave Propagation ◽  
Thermal Shock ◽  
Anisotropic Material ◽  
Energy Deposition ◽  
X Rays ◽  
Two Dimensional ◽  
X Ray ◽  
Deposition Depth

Carbon/Phenolic (C/P), a typical anisotropic material, is an important component of aerospace and often used to protect the thermodynamic effects of strong X-ray radiation. In this paper, we establish the anisotropic elastic-plastic constitutive model, which is embedded in the in-house code “RAMA” to simulate a two-dimensional thermal shock wave induced by X-ray. Then, we compare the numerical simulation results with the thermal shock wave stress generated by the same strong current electron beam via experiment to verify the correctness of the numerical simulation. Subsequently, we discuss and analyze the rules of thermal shock wave propagation in C/P material by further numerical simulation. The results reveal that the thermal shock wave represents different shapes and mechanisms by the radiation of 1 keV and 3 keV X-rays. The vaporization recoil phenomenon appears as a compression wave under 1 keV X-ray irradiation, and X-ray penetration is caused by thermal deformation under 3 keV X-ray irradiation. The thermal shock wave propagation exhibits two-dimensional characteristics, the energy deposition of 1 keV and 3 keV both decays exponentially, the energy deposition of 1 keV-peak soft X-ray is high, and the deposition depth is shallow, while the energy deposition of 3 keV-peak hard X-ray is low, and the deposition depth is deep. RAMA can successfully realize two-dimensional orthotropic elastoplastic constitutive relation, the corresponding program was designed and checked, and the calculation results for inspection are consistent with the theory. This study has great significance in the evaluation of anisotropic material protection under the radiation of intense X-rays.

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