scholarly journals The use of sodium polytungstate as an X-ray contrast agent to reduce the beam hardening artifact in hydrological laboratory experiments

2013 ◽  
Vol 61 (4) ◽  
pp. 347-352 ◽  
Author(s):  
Yoshito Nakashima
Keyword(s):  
Contrast Agent ◽  
Laboratory Experiments ◽  
Source Spectrum ◽  
Ct Scanner ◽  
Beam Hardening ◽  
Two Phase ◽  
X Ray ◽  
X Ray Computed ◽  
Element Bearing ◽  
Sodium Polytungstate

Abstract Iodine is conventionally used as a contrast agent in hydrological laboratory experiments using polychromatic X-ray computed tomography (CT) to monitor two-phase Darcy flow in porous geological media. Undesirable beam hardening artifacts, however, render the quantitative analysis of the obtained CT images difficult. CT imaging of porous sand/bead packs saturated with iodine and tungsten-bearing aqueous solutions, respectively, was performed using a medical CT scanner. We found that sodium polytungstate (Na6H2W12O40) significantly reduced the beam hardening compared with potassium iodide (KI). This result is attributable to the location of the K absorption edge of tungsten, which is nearer to the peak of the polychromatic X-ray source spectrum than that of iodine. As sodium polytungstate is chemically stable and less toxic than other heavy element bearing compounds, we recommend it as a promising contrast agent for hydrological CT experiments.

scholarly journals A Bismuth Metal–Organic Framework as a Contrast Agent for X-ray Computed Tomography

2019 ◽  
Vol 2 (3) ◽  
pp. 1197-1203 ◽  
Author(s):  
Lee Robison ◽  
Lin Zhang ◽  
Riki J. Drout ◽  
Peng Li ◽  
Chad R. Haney ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Contrast Agent ◽  
Metal Organic Framework ◽  
X Ray ◽  
Metal Organic ◽  
X Ray Computed ◽  
Organic Framework

scholarly journals A study on the imaging characteristics of Gold nanoparticles as a contrast agent in X-ray computed tomography

2017 ◽  
Vol 23 (1) ◽  
pp. 9-14 ◽  
Author(s):  
Asghar Mesbahi ◽  
Fatemeh Famouri ◽  
Mohammad Johari Ahar ◽  
Maryam Olade Ghaffari ◽  
Seyed Mostafa Ghavami
Keyword(s):  
Computed Tomography ◽  
Contrast Media ◽  
Contrast Agent ◽  
Hounsfield Unit ◽  
Ct Number ◽  
Agent Based ◽  
X Ray ◽  
Imaging Characteristics ◽  
Tube Potential ◽  
X Ray Computed

AbstractAim: In the current study, some imaging characteristics of AuNPs were quantitatively analyzed and compared with two conventional contrast media (CM) including Iodine and Gadolinium by using of a cylindrical phantom.Methods: AuNPs were synthesized with the mean diameter of 16 nm and were equalized to the concentration of 0.5, 1, 2 and 4 mg/mL in the same volumes. A cylindrical phantom resembling the head and neck was fabricated and drilled to contain small tubes filled with Iodine, Gadolinium, and AuNPs as contrast media. The phantom was scanned in different exposure techniques and CT numbers of three studied contrast media inside test tubes were measured in terms of Hounsfield Unit (HU). The imaging parameters of the noise and contrast to noise ratios (CNR) were calculated for all studied CMs.Results: AuNPs showed 128% and 166% higher CT number in comparison with Iodine and Gadolinium respectively. Also, Iodine had a greater CT number than Gadolinium for the same exposure techniques and concentration. The maximum CT number for AuNPs and studied contrast materials was obtained at the highest mAs and the lowest tube potential. The maximum CT number were 1033±11 (HU) for AuNP, 565±10 (HU) for Iodine, 458±11 for Gadolinium. Moreover, the maximum CNRs of 433±117, 203±53, 145±37 were found for AuNPs, Iodine and Gadolinium respectively.Conclusion: The contrast agent based on AuNPs showed higher imaging quality in terms of contrast and noise relative to other iodine and gadolinium based contrast media in X-ray computed tomography. Application of the AuNPs as a contrast medium in x-ray CT is recommended.

scholarly journals An Improved Algorithm in Porosity Characteristics Analysis for Rock and Soil Aggregate

2014 ◽  
Vol 2014 ◽  
pp. 1-7
Author(s):  
Yanfang Wu ◽  
Xiao Li ◽  
Yu Wang ◽  
Bo Zhang
Keyword(s):  
Compressive Loading ◽  
Soil Aggregate ◽  
Gray Level ◽  
Beam Hardening ◽  
X Ray ◽  
Porosity Evolution ◽  
Evolution Characteristics ◽  
Characteristics Analysis ◽  
X Ray Computed ◽  
Rock And Soil

The rock and soil aggregate (RSA) is a special inhomogeneous multiphase geomaterial. It is crucial for stability of engineering by study of RSA mesodamage characteristic. This paper aims at investigating the porosity evolution characteristics of RSA by X-ray computed tomography (CT) under uniaxial compressive loading. X-ray tomography images were used to extract defects of RSA specimen under different compressive loading. In this paper, we proposed an improved Ostu method to calibrate the beam hardening phenomenon which is caused by X-ray. Also, based on this Ostu method, the outline of rock blocks in RSA is extracted, and the double gray level threshold of soil and rock block is obtained to ensure the reliability of the porosity calculation. We can conclude that the main reason of RSA cracking is the elasticity mismatch between rock blocks and soil, and the porosity evolution of RSA can be divided into four typical stages. These results may be useful to reveal the mesoscopic cracking mechanism and establish mesodamage evolution equation and constitutive relation for RSA.

scholarly journals K-edge Subtraction Computed Tomography with a Compact Synchrotron X-ray Source

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Stephanie Kulpe ◽  
Martin Dierolf ◽  
Benedikt Günther ◽  
Madleen Busse ◽  
Klaus Achterhold ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Contrast Agent ◽  
Imaging Techniques ◽  
X Rays ◽  
Synchrotron Source ◽  
X Ray ◽  
Inverse Compton Scattering ◽  
Inverse Compton ◽  
X Ray Computed ◽  
Compact Light Source

Abstract In clinical diagnosis, X-ray computed tomography (CT) is one of the most important imaging techniques. Yet, this method lacks the ability to differentiate similarly absorbing substances like commonly used iodine contrast agent and calcium which is typically seen in calcifications, kidney stones and bones. K-edge subtraction (KES) imaging can help distinguish these materials by subtracting two CT scans recorded at different X-ray energies. So far, this method mostly relies on monochromatic X-rays produced at large synchrotron facilities. Here, we present the first proof-of-principle experiment of a filter-based KES CT method performed at a compact synchrotron X-ray source based on inverse-Compton scattering, the Munich Compact Light Source (MuCLS). It is shown that iodine contrast agent and calcium can be clearly separated to provide CT volumes only showing one of the two materials. These results demonstrate that KES CT at a compact synchrotron source can become an important tool in pre-clinical research.

Experimental two-phase flow measurement using ultra fast limited-angle-type electron beam X-ray computed tomography

2009 ◽  
Vol 47 (3) ◽  
pp. 369-378 ◽  
Author(s):  
M. Bieberle ◽  
F. Fischer ◽  
E. Schleicher ◽  
D. Koch ◽  
H.-J. Menz ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Electron Beam ◽  
Flow Measurement ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Two Phase ◽  
X Ray ◽  
X Ray Computed ◽  
Limited Angle
Sign in / Sign up

Export Citation Format

Share Document