Researchers Test New MicroCT Imaging System
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.
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.
“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.
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.
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.