<abstract xmlns="http://www.w3.org/1999/xhtml"> 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.</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.

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

National Institute of Advanced Industrial Science and Technology (AIST), Geological Survey of Japan, Central 7, Higashi 1-1-1, Tsukuba, Ibaraki 305-8567, Japan

Journal of Hydrology and Hydromechanics

Iodine is conventionally used as a contrast agent in hydrological laboratory experiments using polychromatic X-ray computed tomography (CT) to monitor...

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

Published Online: Dec 01, 2013

Page range: 347 - 352

DOI: https://doi.org/10.2478/johh-2013-0043

Keywords
Beam hardening artifact, Contrast agent, Darcy flow, Porous media, Sodium polytungstate (SPT), X-ray CT

This content is open access.

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

Published Online: Dec 01, 2013

Page range: 347 - 352

DOI: https://doi.org/10.2478/johh-2013-0043

KeywordsBeam hardening artifact, Contrast agent, Darcy flow, Porous media, Sodium polytungstate (SPT), X-ray CT

This content is open access.

Keywords
Beam hardening artifact, Contrast agent, Darcy flow, Porous media, Sodium polytungstate (SPT), X-ray CT