Researchers Test New MicroCT Imaging System

by | Jun 8, 2018 | News

George Sabo stares at the screen with the intensity of a child who’s just hooked up a new Xbox. Sabo, professor of anthropology and director of the Arkansas Archeological Survey, is looking through – not at – a 500-year-old Caddo artifact.

Researchers, including George Sabo, left, director of the Arkansas Archeological Survey, and Ashly Romero, foreground, doctoral student in anthropology, learn about the new MicroCT system.

Behind him, Claire Terhune, Sabo’s colleague and assistant professor of anthropology, explains the specs and awesome power of the machine that enables Sabo to view this artifact like never before. Along with Wenchao Zhou, assistant professor of mechanical engineering, and Haley O’Brien and Paul Gignac at Oklahoma State University Center for Health Sciences, Terhune and Sabo are principal investigators of the MicroCT Imaging Consortium for Research and Outreach (MICRO), home of the University of Arkansas’ new micro-computed tomography system.

Commonly referred to as “CT” – the same sort of scanning used for medical imaging – computed tomography uses X-ray technology to generate high-resolution 2-D and 3-D representations of an object’s internal and external structure. MicroCT produces images that allow researchers to examine materials down to the micro- (less than or equal to 0.1 millimeter) and even nano-scale (less than 0.001 millimeter).

The ability to visualize bones, teeth and archeological artifacts this way – up close and internally, without dismantling or destroying them – helps researchers understand new and exciting information about evolution, human behavior and cognitive function. But those applications only scratch the surface. MicroCT can also be used for analysis of additive-manufacturing techniques, aerospace technologies, biomedically engineered bone and soft tissue structures, and many other items – basically any object the size of a basketball or smaller and weighing no more than 110 pounds.

Claire Terhune, assistant professor of anthropology.

“The ability to complete our research and learn new and exciting things about the world around us comes from taxpayers and government agencies like the National Science Foundation and the State of Arkansas,” Terhune says. “We want to share what we learn with the public and talk about why we love what we do.”

Managed by the Center for Advanced Spatial Technologies and supported by a $625,000 grant from the National Science Foundation and the University of Arkansas, MICRO is committed to sharing its work with the public. Educators and students can submit samples for scanning at no charge.

For more information, visit the MicroCT Imaging Consortium for Research and Outreach website here or contact Terhune at micro@uark.edu.

MicroCT Images

Rat snake head, prepared using diffusible, iodine-based contrast enhanced computed tomography, or diceCT, a technique that uses Lugol’s iodine – the same sort of iodine used as a disinfectant on a cut – as a staining agent to make soft tissues, such as muscles and nerves, denser and thus visible on x-ray images. By soaking soft-tissue specimens in the iodine solution, the iodine binds to the tissues and becomes radiopaque, or not see-through. Here, the iodine enhances visualization of soft tissues, including the brain, cranial nerves and spinal cord, muscles of the jaw and neck, plus glands, nasal tissues and skin of the head, in addition to bones. This image was recognized by the Royal Society of London and featured in their 2016 online exhibition about scientific visualizations of excellence. Image by Paul Gignac and Nate Kley.

Fetal badger specimen, color-enhanced with diceCT technique. The iodine stain shows detail of soft tissues. Spaces inside the specimen represent portions of the gastrointestinal tract. Image by Haley O’Brien.

Iodine-enhanced scan of a hatchling American alligator head, showing selected soft tissues. The light blue is the brain, purple shows cranial nerves, darker blue is the olfactory bulb, and orange shows eye muscles. Image by Paul Gignac and Nate Kley.
Three-dimensional reconstruction of a juvenile giraffe head in lateral view, prepared using radiopaque vascular injection and CT imaging. This process differs slightly from diceCT in that the arterial system of this specimen was injected with barium-laced latex, which allows the vasculature to show up in considerable detail. For example, between the teeth in this image one can see the arteries of the tongue, part of which is sticking out of this giraffe’s mouth. This image was exhibited at the Tulsa LivingArts Gallery in 2017. Image by Haley O’Brien.
Artificial color rendering of a Caddo tripod bottle. Denser portions of the bottle are shown in warmer colors (yellows), and less dense portions are shown in cooler colors (blues). The small red and yellow flecks in the bottle show dense inclusions in the ceramic material, and the engravings on the surface of the bottle are also visible. Image by Claire Terhune and George Sabo. (Check in next week to learn more about how MicroCT imaging has helped Sabo learn more about this artifact.) 
False-colored, sliced rendering of a blackberry, showing its internal structure, including seeds inside individual berries or “drupelets,” and the central portion of the fruit, or the “torus.” Image by Haley O’Brien and the Department of Horticulture.

Cross-section of a rabbit jaw, focused on the temporomandibular joint, or “TMJ,” showing the internal structure of the bone and a color map representing bone thickness. Warmer colors (reds, oranges) show thicker bone while cooler colors (blues, purples) show thinner bone. This image was produced as part of Claire Terhune’s research on how diet is related to internal bone structure, and whether rabbits raised on different diets show differences in bone thickness. Image by Claire Terhune.

From Spiro, a Caddo archeological site in eastern Oklahoma, a woven “box” lid with copper plating (top) and 3D reconstruction of a cord-wrapped basket fragment with construction elements, including interlayering of plaited plant-fibers, split cane, and woven “yarn” or cordage made from plant fiber and animal fur. Inset shows close-up of braided cordage. Image by Haley O’Brien and George Sabo.
Two-dimensional X-ray image slice, top, and 3D reconstruction, bottom, showing variations in density of a block of sandstone. Image by Haley O’Brien and John Shaw.
Color slide showing exterior and internal structure of a 3D-printed print head for a 3D printer. This new print head is based on a gear pump, which pumps fluid, and was designed for use in next-generation 3D printers that will allow for unlimited printing volume. Image by Haley O’Brien and Wenchao Zhou.