Resurrecting dinosaurs with medical scanners and 3D printers

CT scans and 3D printers are making it possible to see fossils that were previously inaccessible inside rock.

Accurate copies of fossilised bones can now be made from the combined use of computed tomography (CT) scans and 3D printers, according to a paper published in the journal Radiology.

The technique offers scientists a non-destructive way of transporting and handling rare or fragile fossils.

To protect such specimens from damage during transportation, the fossils are often stored in plaster jackets or casts. These jackets must be strong enough to protect the fossils, but should also separate easily from the specimen when removed.

It is during the removal of the plaster and surrounding sediment that the fossil is in danger of material loss or even destruction. This typically occurs when the plaster is stuck fast to the bone.

(A 3D print of a fossil (right) next to the original still inside a plaster jacket. Image: Courtesy of Radiology and RSNA)

A group of German researchers found that, by using CT and 3D printers, they could separate fossilised bone from its surrounding sediment matrix in a way that would not harm the specimen, then produce a 3D copy of it.

Applying this method to an unidentified fossil from the Museum für Naturkunde in Berlin, the researchers scanned the bone with a 320-slice multi-detector system to show up the different attenuation (absorption of radiation) through the bone and the surrounding sediment matrix, depicting clearly the fossilised vertebra.

The scan also provided information on the condition and integrity of the specimen, like otherwise unknown fractures, and helped the researchers build an accurate reconstruction of the fossil.

Then using a laser sintering system – a process which uses high-powered lasers to fuse materials by adding thin horizontal layers of plastic – an accurate 3D copy of the fossil was produced.

(An enlarged 3D copy of a 380 million year old coelacanth skull found near Fitzroy Crossing, Western Australia. Image: John Long)

The impact on palaeontology
According to Richard Brian Gunderman, a professor of radiology at Indiana University who was not involved in the study, CT scanners are able to determine the exact structural dimensions of an object, down to fractions of a millimetre.

This data can then be used to construct a replica so precise that objects of great historical interest, like Stradivarius violins, have been created to sound remarkably similar to the originals.

“Such a technology has been a boon to palaeontologists in the past few years,” said John Long, strategic professor in palaeontology at Flinders University.

“Once we relied on meticulous time-consuming methods to prepare delicate fossils out of the rock and, even then, we could only see their external features. Now, using high-resolution micro-CT scanners and synchrotrons [particle accelerators], we can investigate every nook and cranny of the fossil right down to individual cells and tissue structures without having to risk damaging the specimen.

“Combined with advanced 3D printing, we can now slice though the ancient fossil skulls and print them in halves showing the full anatomy in clear definition. This will no doubt revitalise palaeontology.”

(A 3D scan of a 380 million-year-old Gogonasus fish skull by Tim Senden and ANU Vizlab.)

Ahi Sema Issever, from the Charité Campus Mitte in Berlin and one of the study’s authors, explained: “The most important benefit of this method is that it is non-destructive so the risk of harming the fossil is minimal. In addition, not only does this method allow for a global exchange of rare fossils in any quantity, data on the specimens can also be digitally shared between research institutes, museums and schools while protecting the original fossil.”

Darren Curnoe, associate professor at the University of New South Wales, agreed, saying: “Famous fossils like the Taung Child in South Africa - the very first ancient ape-like creature found in our human evolutionary tree - has been quite badly damaged following almost 90 years of study by scientists.

“Almost everyone who sees the fossil wants to take a couple of measurements of their own, and by doing so, is damaging these priceless pieces of our collective heritage. We need to do better, and such technology might just be the answer.”

A note of caution
Although supportive of the technological breakthrough in this study, Professor Long warned that researchers must not rely too heavily on tomographic imagery and 3D printing to draw their conclusions.

“It is important to carefully study the preservational biases of the original fossil first to determine how reliable a computer-generated image will be. In some cases, replacement of bone by other minerals or the presence of solid inclusions can effect the quality of CT images and affect 3D printing results.

“Scientists still need to study the original specimens in detail first, and then make interpretations using CT tomography and 3D printing.”

(A scanned 400 million-year-old placoderm eye capsule found in Taemas near Canberra. Image: Tim Senden)

Associate Professor Curnoe agreed, saying: “Any model made from CT scans must properly distinguish actual bone from missing bone, or even from materials like plaster, that had been used in the past to reconstruct missing bones in the fossils. This is particularly important since most fossils found are incomplete or distorted.

“In the end, there is nothing like seeing the real thing to fully understand the anatomy and the state of preservation of a fossil. But, for the sort of work many scientists do, especially postgraduate students, 3D models would be incredibly useful at a time when funding can be very hard to get.”

Beyond fossils
Some experts speculate that the findings from this study will benefit the medical field, like building and fitting implants in orthopaedic surgery. Others feel that the technique could be used to model real bones and other tissues, such as cadavers that have been preserved in ice or peat bogs.

Martin Baumers, a research fellow at the University of Nottingham, would like to see the implementation of a virtual library and data infrastructure for such 3D data and designs. He believes that it would aid collaborative research, allowing experts from different disciplines to share and retrieve 3D models for 3D printing or other scientific, even commercial, usage.

For Professor Long, the biggest breakthrough will come when palaeontologists possess the ability to make portable machines to take into the field and scan fossils, still buried under the rock layers, to determine the full extent of the fossil before excavating it.

This article was originally published at The Conversation. Read the original article.The Conversation

A scan of a 380million-year-old tooth from a fossil shark. (Image: Tim Sendon)
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How the Night Tube could give London’s mice that Friday feeling

London Underground’s smaller inhabitants might be affected by the off-squeak service – and learn when the weekend’s coming up.

What will the mice who live in the Tube network make of the new all-night service? Half a million of them are thought to have made the London Underground their home – and will be in for a surprise when the Victoria and Central lines keep running this weekend.

The Londonist is concerned the mice “are unlikely to get any sleep” with the new Night Tube, and may move to the District line instead. Yet a number of scientists point out to the New Statesman that mice are nocturnal creatures, most likely to sleep while the lights are on and the trains are running.

So will they get on board with the change – or make a run for different platforms on other lines?

The bad news:

“When the Tube’s away, the mice will play,” is how the rhyme (almost) goes. 

Many have come to know  and even love  the mischiefs of the mice who stream off the tracks and out of the tunnels as the stations close at night, in search of discarded morsels of Maccy D. And until now, they’ve had a good few hours to conduct such galavanting in peace. But the new system means they will have to re-structure their sleep and foraging cycles, or “circadian rhythms”. 

“The presence of night trains should upset several of these entrainment factors (or zeitgebers = time givers) leading to disturbances in their behaviours,” explains Professor Patrick Nolan, from MRC Harwell, an international centre for mouse genetics. 

“When you fly across the Atlantic, for example, it takes a few days to adapt, you feel a bit groggy, don't perform as well as you usually do, don't eat well, etc. You soon adapt to the change. But if there are constant disruptions like this, the effect may be more severe and long-lasting. And this is how the schedule changes in the Underground might affect the resident mice.” 

So it's the constant switching between the week and weekend schedules that could leave the mice  and Tube drivers  most cheesed off. Agoraphobia (fear of open spaces) and photophobia (sensitivity to light) are two possible effects of the resulting anxiety, and their mating patterns and liver functions are also likely to be disturbed.

The good news:

Yet it is unlikely mice will be leaving the Night Tubes for good. 

The more time we humans have to drop our dinners, the larger the menu becomes for the mice (researchers tell me that strawberry milk and Wheetos are particularly favoured fare).

“Mice are active most of the time – so more trains at night hours will not make such a difference to them,” say the RSPCA’s wildlife officers. “In fact, it may help as it may provide more foraging opportunities.”

They’ve also faced worse before. The London Transport Museum reminds us that, during the Second World War, cats were employed to counter vermin on the network (spot the cat in the 1940s TfL workers' canteen below).


Credit: London Transport Museum

For Dr Samuel Solomon at UCL, there is plenty to suggest the mice will successfully adapt. His study of mouse reflexes shows how they respond to various visual stimuli – and can start running within one-tenth of a second. “There might be cues they pick up – if people clean the station differently on Fridays, for instance.”

The tracks’ electric current may no longer be entirely switched off (if it ever was), but their whiskers’ sensitivity to vibrations could help them juggle their escapades to fit around the Night Tube’s less frequent service.

What Dr Soloman can’t yet predict is whether the mice will start to anticipate that Friday feeling: “It will be interesting to see whether they can learn that Friday is Friday”.

All in all, the Tube mice seem well set for the Night Tube’s new challenge. Who knows, they may soon gain the confidence of their 24/7 brothers in New York – and start ordering take-out...

India Bourke is the New Statesman's editorial assistant.