Имитационная модель оценки артефактов немоноэнергетичности и рассеяния в компьютерной томографии

2021 ◽  
Vol 7 ◽  
pp. 37-51
Author(s):  
С.П. Осипов ◽  
Х.Д. Мирзоев ◽  
С.В. Чахлов ◽  
О.С. Осипов ◽  
Е.Ю. Усачев
Keyword(s):  
Computed Tomography ◽  
Simulation Model ◽  
Attenuation Coefficient ◽  
Cross Sections ◽  
Axial Symmetry ◽  
Reverse Transformation ◽  
Linear Attenuation Coefficient ◽  
Parallel Beam ◽  
Beam Hardening ◽  
Modeling Algorithm

A simulation model for estimating the beam-hardening and scattering in computed tomography in the geometry of a parallel beam is proposed on the example of inhomogeneous objects with axial symmetry. The modeling algorithm consists of a block of formation of projections and a block of reconstruction of images of object cross sections based on the Abel reverse transformation. The developed algorithm is implemented as a MathCad program. The efficiency of the algorithm and program is demonstrated by the example of a multilayer ball. Estimates of the beam hardening artifacts and scattering of the simulation model are compared with experimental estimates for the radial distributions of the linear attenuation coefficient.

Evaluation of a Combined Transmission and Scattering Approach to Composition Imaging of Industrial Samples

1991 ◽  
Vol 35 (B) ◽  
pp. 1235-1241
Author(s):  
T. H. Prettyraan ◽  
R. P. Gardner ◽  
J. C. Russ ◽  
K. Verghese
Keyword(s):  
Computed Tomography ◽  
Attenuation Coefficient ◽  
Dual Energy ◽  
Linear Attenuation Coefficient ◽  
Energy Transmission ◽  
Transmission Computed Tomography ◽  
Coefficient Distribution ◽  
Industrial Samples ◽  
The Given

Composition imaging of industrial samples has been reported using dual energy and multiple energy transmission computed tomography [1,2]. The simplest approach utilizes monoenergetic sources to obtain tomographs of a sample at two different energies. Each tomograph represents the linear attenuation coefficient distribution of the sample at the given source energy.

Improvement of Gamma Radiation Shielding Features for Fluorophosphate Glasses Doping with Sm2O3 (PZBKNA)

2020 ◽  
Vol 15 (11) ◽  
pp. 1374-1380
Author(s):  
H. Almohiy ◽  
M. Saad ◽  
Y. M. AbouDeif ◽  
Iwona Grelowska ◽  
M. Reben ◽  
...  
Keyword(s):  
Attenuation Coefficient ◽  
Cross Sections ◽  
Radiation Safety ◽  
Effective Atomic Number ◽  
Mean Free Path ◽  
Mass Attenuation Coefficient ◽  
Radiation Shielding ◽  
Linear Attenuation Coefficient ◽  
Ordinary Concrete ◽  
Materials Used

This research reported on the radiation safety characteristics of doped fluorophosphate glasses with heavy rare earth lanthanide (Sm2O3) in the composition 40P2O5/30ZnO/20BaF2/3.8K2TeO3/1.2Al2O3/5.0Nb2O5/30000 ppm Sm2O3 and 40P2O5/30ZnO/20BaF2/3.8K2TeO3/1.2Al2O3/5.0Nb2O5/40000 ppm Sm2O3 in mol%. The parameters for shielding like that mass attenuation coefficient, MAC, linear attenuation coefficient, LAC, tenth value layers, TVL, half-value layers, HVL, effective atomic number, (Zeff), mean free path, MFP, electron density, Neff, electronic cross-sections, ECS, and total atomic cross-sections, ACS, were calculated between 0.015 and 15 MB of preparation glasses. The protection parameters of the current glasses are good in comparison to industrial materials used for nuclear shieldings, such as glass RS 253, ordinary concrete (OC), hematite serpenite (HS), or basalt magnet (BM). From the above mention results, the prepared glasses can be used as radiation safety materials.

scholarly journals A Mineral X-ray Linear Attenuation Coefficient Tool (MXLAC) to Assess Mineralogical Differentiation for X-ray Computed Tomography Scanning

Minerals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 441
Author(s):  
Lunga Bam ◽  
Jodie Miller ◽  
Megan Becker
Keyword(s):  
Computed Tomography ◽  
Attenuation Coefficient ◽  
Data Bank ◽  
Linear Attenuation Coefficient ◽  
Chemical Formula ◽  
Attenuation Coefficients ◽  
X Ray ◽  
Computed Tomography Scanning ◽  
X Ray Computed ◽  
Tomography Scanning

X-ray computed tomography (XCT) is becoming one of the most important techniques in the geosciences. The technique relies on linear attenuation coefficient differences in order to reveal the internal structure of the rocks. In this work, we present a new excel macro tool, called MXLAC, which is a data bank with an excel interface that uses density, X-ray energy and the mineral chemical formula to allow users to calculate mineral linear attenuation coefficients that can then be used to determine discrimination between mineral pairs. Elements within a mineral and specified by the chemical formula, determine how the X-ray beam is attenuated. Analysis of a variety of scanned mineral pairs with similar densities and attenuation coefficients indicates that an attenuation coefficient difference of greater than or equal to 6% at 45.5 keV effective X-ray energy is required for effective discrimination between two minerals using XCT with single energy scanning. This means that mineral pairs, such as quartz and pyrophyllite cannot be discriminated using the current XCT instruments due to the fact that the attenuation coefficient difference is less than 1.9% at 45.5 keV effective X-ray energy. Garnets and a variety of other minerals were used as examples to illustrate the importance of knowing the actual chemical formula of the mineral to demonstrate whether they can be partially or fully discriminated from each other.

Morphology and Affinities of Ampelocissites Seeds (Vitaceae: Ampelopsis clade) from the Paleogene of Texas, USA

2020 ◽  
Vol 45 (3) ◽  
pp. 478-482
Author(s):  
Steven R. Manchester
Keyword(s):  
Computed Tomography ◽  
Cross Sections ◽  
Seed Coat ◽  
Ct Scanning ◽  
Seed Morphology ◽  
Early Eocene ◽  
Micro Computed Tomography ◽  
X Ray ◽  
Fossil Seeds ◽  
Fossil Genus

Abstract—The type material on which the fossil genus name Ampelocissites was established in 1929 has been reexamined with the aid of X-ray micro-computed tomography (μ-CT) scanning and compared with seeds of extant taxa to assess the relationships of these fossils within the grape family, Vitaceae. The specimens were collected from a sandstone of late Paleocene or early Eocene age. Although originally inferred by Berry to be intermediate in morphology between Ampelocissus and Vitis, the newly revealed details of seed morphology indicate that these seeds represent instead the Ampelopsis clade. Digital cross sections show that the seed coat maintains its thickness over the external surfaces, but diminishes quickly in the ventral infolds. This feature, along with the elliptical chalaza and lack of an apical groove, indicate that Ampelocissites lytlensis Berry probably represents Ampelopsis or Nekemias (rather than Ampelocissus or Vitis) and that the generic name Ampelocissites may be useful for fossil seeds with morphology consistent with the Ampelopsis clade that lack sufficient characters to specify placement within one of these extant genera.

scholarly journals Comparative Morphological Studies of the Stifle Menisci in Donkeys, Goats and Dogs

2019 ◽  
Vol 36 (02) ◽  
pp. 072-084 ◽  
Author(s):  
Mohamed M.A. Abumandour ◽  
Naglaa Fathi Bassuoni ◽  
Samir El-Gendy ◽  
Ashraf Karkoura ◽  
Raafat El-Bakary
Keyword(s):  
Computed Tomography ◽  
Cross Sections ◽  
Medial Meniscus ◽  
Lateral Meniscus ◽  
Current Work ◽  
Medial Condyle ◽  
Morphological Studies ◽  
Stifle Joint ◽  
Meniscofemoral Ligament ◽  
Anatomical Information

AbstractThe present work aims to provide more anatomical information on the stifle joint of the investigated species using computed tomography with gross anatomical cross-sections. The current work analyzed the stifle joint of the pelvic limbs of 12 adult donkeys, goats and dogs of both genders. The medial condyle of the femur was larger than the lateral one in the donkey, while it was smaller and lower than the lateral one in the goat and in the dog. The unsuitable femoral and tibial condyles were adapted by the presence of menisci. In the donkey, the medial meniscus was crescentic in shape, but it was semicircular in the goat, while in the dog, the medial and lateral menisci were C-shaped. In the donkey, the medial meniscus was larger than the lateral one, but in the goat and in the dog, the lateral meniscus was the largest, and more concave and thicker. The lateral meniscus was semicircular in the donkey, but it was shaped like an elongated kidney in the goat. In the goat and in the dog, the central border of two menisci was thin, concave and notched centrally. The meniscal ligaments included cranial and caudal ligaments of the medial and lateral menisci, and meniscofemoral ligament of the lateral meniscus. In the dog, the cranial ligament of the medial meniscus was absent, and the medial meniscus had no bony attachment to the tibia but it attached to the transverse intermeniscal ligament, which connected the cranial horn of the medial meniscus with the cranial ligament of the lateral meniscus. The meniscofemoral ligament connected the caudal pole of the lateral meniscus with the intercondyloid fossa of the femur.

scholarly journals X-ray Shielding, Mechanical, Physical, and Water Absorption Properties of Wood/PVC Composites Containing Bismuth Oxide

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2212
Author(s):  
Worawat Poltabtim ◽  
Ekachai Wimolmala ◽  
Teerasak Markpin ◽  
Narongrit Sombatsompop ◽  
Vichai Rosarpitak ◽  
...  
Keyword(s):  
Impact Strength ◽  
Water Absorption ◽  
Attenuation Coefficient ◽  
Bismuth Oxide ◽  
Morphological Properties ◽  
Linear Attenuation Coefficient ◽  
X Rays ◽  
Equivalent Thickness ◽  
X Ray ◽  
The Impact

The potential utilization of wood/polyvinyl chloride (WPVC) composites containing an X-ray protective filler, namely bismuth oxide (Bi2O3) particles, was investigated as novel, safe, and environmentally friendly X-ray shielding materials. The wood and Bi2O3 contents used in this work varied from 20 to 40 parts per hundred parts of PVC by weight (pph) and from 0 to 25, 50, 75, and 100 pph, respectively. The study considered X-ray shielding, mechanical, density, water absorption, and morphological properties. The results showed that the overall X-ray shielding parameters, namely the linear attenuation coefficient (µ), mass attenuation coefficient (µm), and lead equivalent thickness (Pbeq), of the WPVC composites increased with increasing Bi2O3 contents but slightly decreased at higher wood contents (40 pph). Furthermore, comparative Pbeq values between the wood/PVC composites and similar commercial X-ray shielding boards indicated that the recommended Bi2O3 contents for the 20 pph (40 ph) wood/PVC composites were 35, 85, and 40 pph (40, 100, and 45 pph) for the attenuation of 60, 100, and 150-kV X-rays, respectively. In addition, the increased Bi2O3 contents in the WPVC composites enhanced the Izod impact strength, hardness (Shore D), and density, but reduced water absorption. On the other hand, the increased wood contents increased the impact strength, hardness (Shore D), and water absorption but lowered the density of the composites. The overall results suggested that the developed WPVC composites had great potential to be used as effective X-ray shielding materials with Bi2O3 acting as a suitable X-ray protective filler.

scholarly journals Enhancement of the Shielding Capability of Soda–Lime Glasses with Sb2O3 Dopant: A Potential Material for Radiation Safety in Nuclear Installations

2020 ◽  
Vol 11 (1) ◽  
pp. 326
Author(s):  
M.I. Sayyed ◽  
K.A. Mahmoud ◽  
O.L. Tashlykov ◽  
Mayeen Uddin Khandaker ◽  
M.R.I. Faruque
Keyword(s):  
Attenuation Coefficient ◽  
Elastic Moduli ◽  
Gamma Ray ◽  
Radiation Safety ◽  
Soda Lime ◽  
Mass Attenuation Coefficient ◽  
Transmission Factor ◽  
Linear Attenuation Coefficient ◽  
Neutron Shielding ◽  
Removal Cross Section

Elastic moduli were theoretically computed using the Makishima–Mackenzie model for SiO2–Na2O–CaO glasses doped with Sb2O3 contents. The calculated elastic moduli (Young’s, bulk, shear, and longitudinal modulus) were observed to increase with an increase in the Sb2O3 contents. The microhardness showed an increase, while Poisson’s ratio decreased with the rise of the Sb2O3 contents. In addition, gamma-ray and neutron shielding parameters were evaluated for the investigated glasses. The linear attenuation coefficient (LAC) was simulated using the Monte Carlo N-particle transport code (MCNP-5). Other parameters, such as the mass attenuation coefficient (MAC), transmission factor (TF), and half-value layer, were calculated based on the simulated LAC. The addition of Sb2O3 content was observed to enhance the investigated glasses’ shielding parameters, where the highest LAC was achieved for the SCNSb10 glass with 10 mol% Sb2O3 and decreased from 0.441 to 0.154 cm−1 at gamma energies between 0.248 and 1.406 MeV. Furthermore, the fast neutron effective removal cross-section (∑R) was computed theoretically. The calculated results showed that the highest ∑R was equal to 0.0341 cm2g−1 and was obtained for the SCNSb0 glass, which had no Sb2O3 content, while the lowest ∑R was equal to 0.0286 cm2 g−1 for the SCNSb10 glass sample. The present work was carried out to examine the advantages of the soda–lime glasses with different Sb2O3 contents in several photon shielding applications, especially for radiation safety in nuclear installations.

scholarly journals A Direct Sinogram Correction Method to Reduce Metal-Related Beam-Hardening in Computed Tomography

IEEE Access ◽  
2019 ◽  
Vol 7 ◽  
pp. 128828-128836 ◽  
Author(s):  
Sung Min Lee ◽  
Taigyntuya Bayaraa ◽  
Hosan Jeong ◽  
Chang Min Hyun ◽  
Jin Keun Seo
Keyword(s):  
Computed Tomography ◽  
Correction Method ◽  
Beam Hardening
Sign in / Sign up

Export Citation Format

Share Document