X-ray vision just got cooler. A technique developed in recent years boosts researchers’ ability to see through the body and capture high-resolution images of animals inside and out.
This special type of 3-D scanning reveals not only bones, teeth and other hard tissues, but also muscles, blood vessels and other soft structures that are difficult to see using conventional X-ray techniques.
Researchers have been using the method, called diceCT, to visualize the internal anatomy of dozens of different species at Duke’s Shared Materials Instrumentation Facility (SMIF).
There, the specimens are stained with an iodine solution that helps soft tissues absorb X-rays, then placed in a micro-CT scanner, which takes thousands of X-ray images from different angles while the specimen spins around. A computer then stitches the scans into digital cross sections and stacks them, like slices of bread, to create a virtual 3-D model that can be rotated, dissected and measured as if by hand.
Here’s a look at some of the images they’ve taken:
If you get flushed after a workout, you’re not alone — the Caribbean anemone shrimp does too.
Recent Duke Ph.D. Laura Bagge was scuba diving off the coast of Belize when she noticed the transparent shrimp Ancylomenes pedersoni turn from clear to cloudy after rapidly flipping its tail.
To find out why exercise changes the shrimp’s complexion, Bagge and Duke professor Sönke Johnsen and colleagues compared their internal anatomy before and after physical exertion using diceCT.
In the shrimp cross sections in this video, blood vessels are colored blue-green, and muscle is orange-red. The researchers found that more blood flowed to the tail after exercise, presumably to deliver more oxygen-rich blood to working muscles. The increased blood flow between muscle fibers causes light to scatter or bounce in different directions, which is why the normally see-through shrimp lose their transparency.
Peer inside the leg of a mouse
Duke cardiologist Christopher Kontos, M.D., and MD/PhD student Hasan Abbas have been using the technique to visualize the inside of a mouse’s leg.
The researchers hope the images will shed light on changes in blood vessels in people, particularly those with peripheral artery disease, in which plaque buildup in the arteries reduces blood flow to the extremities such as the legs and feet.
The micro-CT scanner at Duke’s Shared Materials Instrumentation Facility made it possible for Abbas and Kontos to see structures as small as 13 microns, or a fraction of the width of a human hair, including muscle fibers and even small arteries and veins in 3-D.
Take a tour through a tree shrew
DiceCT imaging allows Heather Kristjanson at the Johns Hopkins School of Medicine to digitally dissect the chewing muscles of animals such as this tree shrew, a small mammal from Southeast Asia that looks like a cross between a mouse and a squirrel. By virtually zooming in and measuring muscle volume and the length of muscle fibers, she hopes to see how strong they were. Studying such clues in modern mammals helps Kristjanson and colleagues reconstruct similar features in the earliest primates that lived millions of years ago.
Try it for yourself
Students and instructors who are interested in trying the technique in their research are eligible to apply for vouchers to cover SMIF fees. People at Duke University and elsewhere are encouraged to apply. For more information visit https://smif.pratt.duke.edu/Funding_Opportunities, or contact Dr. Mark Walters, Director of SMIF, via email at firstname.lastname@example.org.
Located on Duke’s West Campus in the Fitzpatrick Building, the SMIF is a shared use facility available to Duke researchers and educators as well as external users from other universities, government laboratories or industry through a partnership called the Research Triangle Nanotechnology Network. For more info visit http://smif.pratt.duke.edu/.