We know a lot about the jaws of the Tyrannosaurus rex, from the bite force of a baby dinosaur to the way adults crunched on their prey like an alligator. Now, medical researchers have used a CT (computed tomography) scan to reveal that these ancient carnivores suffered from bone disease.
A new study, led by radiologist Charlie Hamm from Charité University Hospital in Berlin, used a clinical CT scanner to take a look at the 68-million-year-old lower jawbone of a T-rex skeleton.
Named “Tristan Otto”, the fossilised skeleton was uncovered in Montana in 2010 and is now in the Natural History Museum in Berlin.
Along with a normal CT scan, the team also used a technique called dual-energy computed tomography (DECT). This scans the sample with X-rays at two different energy levels, giving information about tissue composition and disease processes invisible to a single-energy CT scan.
For example, the CT scan of a portion of the jaw called the left dentary revealed thickening and a mass on its surface. Then the DECT detected an accumulation of fluorine within the mass. The researchers say that together, these indicate that the T-rex had tumefactive osteomyelitis, an infection of the bone.
Until recently, fossils were largely studied by invasive sampling and analysis that could potentially destroy a sample. But non-invasive techniques like CT scanning have become game-changing over the past few decades.
For instance, micro-CT scanning has shown that a pterodactyl had opposable thumbs, and synchrotron microtomography recently revealed a 230-million-year-old beetle species trapped within fossilised dinosaur poo.
The addition of the DECT technique could have further significant applications in palaeontology.
“While this is a proof-of-concept study, non-invasive DECT imaging that provides structural and molecular information on unique fossil objects has the potential to address an unmet need in paleontology, avoiding defragmentation or destruction,” says Hamm.
Co-author of the study, vertebrate palaeontologist Oliver Hampe from the Natural History Museum in Berlin, agrees.
“The DECT approach has promise in other paleontological applications, such as age determination and differentiation of actual bone from replicas,” he explains.
“The experimental design, including the use of a clinical CT scanner, will allow for broad applications.” The research was presented this week at the annual meeting of the Radiological Society of North America.