Archaeologists may soon unravel the mysteries of ancient Egypt using a new imaging technique that offers a better look inside mummies without removing a single piece of wrapping.
The new kind of CT scan has been successfully tested on cat mummies from the collections of the South Australian Museum. While the exact ages of these mummies are unknown, feline mummies were fairly common in Egypt from about 600 B.C. until A.D. 250.
Typical CT scans use a single type of x-ray to take images of an object from multiple angles and then create a digital image of the insides. Such scans can tell the difference between muscle and bone based on their relative density. But this can present challenges for mummies: As they get older, their skin and muscles dry up and become denser, while the bones lose marrow and become less dense.
The new technique, known as atomic number imaging, instead uses two kinds of x-rays to peer inside stuff and figure out the hidden composition based on a material’s atomic number—one of the defining characteristics of a chemical element. For instance, the scans can distinguish between bones filled with calcium and phosphorous and muscle, which is mostly carbon.
“It’s a technique that can be done on any CT scanner,” says lead author James Bewes, a radiology resident at the Royal Adelaide Hospital in Australia, who describes the work in the August issue of the Journal of Archaeological Science.
“We can dive that little bit deeper into the makeup of what we’re imaging,” Bewes says. “We’re trying to tell how they lived and how they died through their bones and through their muscles.”