Dinosaur Fossils Recreated Harnessing CT Scanners and Laser Sintering

3-D print of a fossilized dinosaur vertebra next to a plaster jacket
Photograph showing the 3D print of a fossilized dinosaur vertebra (right) next to an unprepared plaster jacket, enclosing the original fossil (Credit: Radiology and RSNA).

A new study has shown that data collected from computed tomography (CT) scanners can be utilized to manufacture more accurate recreations of dinosaur fossils, in conjunction with 3-dimensional printing technologies. A combination of these techniques was recently employed to reestablish the identity of a preserved fossil – derived from a long-necked herbivorous dinosaur – whose identity had been lost, following a World War II era bombing on a Berlin museum.

Recent research, conducted by a group of German scientists, suggests that harnessing the combined powers of CT scanners and 3D printers to produce fossilized bones is not only more accurate, but is also a highly desirable, non-destructive method.

Fossils are typically preserved in plaster casts to protect them from damage during transportation or storage. In order for scientists to investigate the fossilized remains, in greater depth, they must separate the specimen from the plaster cast and sediment that encases it. Alas, this procedure can be time-consuming and dangerous, potentially leading to loss of material and damage of the highly fragile remains. The use of a preparator’s chisel, upon attempting to pry apart bone from superfluous material, can often lead to fossil fractures and crumbling.

Reestablishing a Lost Identity

Study author Ahi Sema Issever, alongside his colleagues, based at the Department of Radiology at Charité Campus Mitte in Berlin, used the new CT scanner/3D printer method to explore an unidentified fossil provided by the Museum für Naturkunde, a major natural history museum in Berlin that houses over 30 million paleontological, mineralogical and zoological samples.

The museum had been subjected to bombing raids, during World War II. A number of fossilized specimens were buried during the explosive incident in the rubble of the building’s basement and, resultantly, the categorization and identity of the amassed collection had become confused.

Halberstadt field map showing the original excavation sites
Original excavation field map, obtained during 1929. The inset shows the drawing of the vertebral fossil (Credit: Radiology and RSNA).

This issue was further compounded by the presence of two separate sets of stored dinosaur fossils, obtained from different expeditionary ventures; the first set of specimens originated from a Tanzania expedition, which culminated in the retrieval of around 235 tons of fossils, whereas the second set was discovered in Halberstadt, Germany. Other fossil, meanwhile, were less lucky and had been pulverized into dust.

Ever since the bombing, museum officials have laboriously trawled through the plaster jackets to try and deduce the identity of the countless remains. It is not until recently that scientists have sought to find novel techniques to accelerate the arduous task.

Recreating the Dinosaur Fossil

Taking one of these mysterious specimens, the research team employed a 320-slice multi-detector system. As the X-rays of the CT scanner are beamed towards the preserved fossil, in a variety of planes, the differences in attenuation between the fossil and the enclosing matrix are used to generate a 3-dimensional image of the stored specimen. In essence, the technique could be used to peer inside the sample and discern fossil from rock and plaster.

Virtual reconstructions of the vertebral body
Virtual reconstructions of the vertebral body, collected from the CT scanning technique. Multiple fractures are seen running along the anterior rim of the structure (Credit: Radiology and RSNA).

The scientists then used the new CT-obtained images and compared them to old drawings of dinosaur fossils, created during their original excavation. Eventually, they stumbled across drawings from the Halberstadt excavation that appeared to match up with the image acquired from their CT scan.

The CT scanner did not merely help with reestablishing its identity, however. The scans also helped to reveal the overall integrity of the sample, which was found to possess a number of fractures, alongside partial destruction of the front portion of the vertebral section.

The group then used a procedure called selective laser sintering (SLS) to produce a physical recreation of the fossil. This technology involves use of a programmable laser, which melts down a plastic power by subjecting it to extremes of temperatures. The melting occurs on a layer-by-layer basis, and subsequently molds the plastic into the desired shape.

“The digital dataset and, ultimately, reproductions of the 3-D print may easily be shared, and other research facilities could thus gain valuable informational access to rare fossils, which otherwise would have been restricted… Just like Gutenberg’s printing press opened the world of books to the public, digital datasets and 3-D prints of fossils may now be distributed more broadly, while protecting the original intact fossil.”

Issever also ruminates upon some of the other principal advantages of 3D printing techniques, which are rapidly plummeting in cost. 3D models, collected from CT scans, for example, also allows dissemination of digital models that can be recreated using 3D printers. Issever believes that the future lies in 3D printing, arguing it to be a great boon to advancement of scientific exchange and sees the technology’s application in research settings, museums and educational institutions.

By James Fenner

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