Computed Tomography:
High Resolution X-ray Scanning
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A paleontologist wants to examine the embryo fossilized inside a prehistoric egg. A geologist needs to determine the complex relationships among minerals at the center of a meteorite. Traditionally these scientists would have no choice but to saw the egg in half or break the rock, damaging their specimens irreversibly. Unfortunately, these dramatic alterations could also lead to erroneous scientific conclusions. The new High Resolution X-ray CT Scanner at The University of Texas at Austin has made it possible to observe the interior of opaque, solid objects through computer-animated, three-dimensional images, without altering the objects in any way. The CT (Computed Tomography) Scanner is not only preserving the object under investigation, it's raising the process of scientific inquiry to a higher level. From the outside, the scanner looks like nothing more than a big gray box about the size of a roomy, walk-in closet. But the box is producing amazing breakthroughs in scientific research. In April 1997, with major support from the W. M. Keck Foundation of Los Angeles and additional support from the National Science Foundation, the Department of Geological Sciences at UT Austin fired up the big gray box and inaugurated the first high resolution X-ray CT Scanner dedicated to academic research. The scanner X-rays the object in thin, consecutive "slices" that are assembled on a computer in rotating, animated, three-dimensional images. UT's scanner can resolve details as small as a few tens of microns in size, even within objects made of high-density materials such as rock, bone, ceramic, or metal. Conventional methods of examination destroy the original object and supply a less complete picture of it. Because the scanner does not actually touch the sample, it allows geologists and paleontologists to examine the interior of rare objects such as meteorites and fossils without harming them.
The most dramatic research discoveries so far have been in geology. "The tool allows us to actually see the 3-D pathways along which oil flows through rock formations. There was really no way to do this in the past," says Bill Carlson, leader of the UTCT team, former chairman of the UT Department of Geological Sciences, and associate dean of the College of Natural Sciences.
The scanner also helps geologists to examine how other fluids move through the earth. "We've been looking at how contaminants move through soil and threaten hydrological systems," Carlson explains. Two other University of Texas faculty members are Carlson's partners in the project, Professor Tim Rowe of the Department of Geological Sciences and Professor John Kappelman of the Department of Anthropology. The scanner has been in constant use since it went on-line in 1997. In addition to UT scientists, researchers from dozens of other leading institutions have come to Austin to use this state-of-the-art instrument. Among the most prominent are researchers from NASA, the Smithsonian, the Federal Highway Administration, Columbia University's Woods Hole Oceanographic Institution, Waseda University (Japan), the American Museum of Natural History, and the Oakridge National Laboratories. One of the purposes of the UTCT facility is to provide accessible, cutting-edge scanning services for the national and international scientific community. In March 1999, the National Science Foundation agreed to support the lab as a shared multi-user facility, thus designating it as a leading national research center. The facility also includes a multi-platform computer lab that can be made available to outside researchers who come to UT to use the scanner and work with their data. For information about UTCT, researchers should visit the UTCT website, email ctlab@maestro.geo.utexas.edu, or phone 512-471-0260. Support from the W. M. Keck Foundation The W. M. Keck Foundation was at the top of Bill Carlson's list when he began seeking funding for the project. W. M. Keck, founder of the Superior Oil Company, relied on imagination, innovation, and emerging technologies to build his company. Under his leadership, the Superior Oil Company became one of the largest independent oil-producing companies of its time. "The W. M. Keck Foundation is renowned for seeking out projects that have a strong educational component and are at the leading edge of innovation," explains Carlson. Bob Dorsey, a former director of the W. M. Keck Foundation board, is pleased that UT earned this prestigious grant. "The Keck Foundation has very strict guidelines governing awards. The University of Texas put forward a very convincing case," he says. Bob Dorsey received a degree in chemical engineering from UT in 1940. He went to work for the Gulf Oil Company after graduation and remained with them his entire career, eventually becoming chairman and president of the corporation. In 1968 he was named a Distinguished Alumnus of The University of Texas at Austin. By Thomas Tarbox Kiersted,
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