X-raying fossils

Scientists are using another method to visualize details contained in fossils: x-rays. Here are some examples:

• Researchers at Ghent University in Belgium used Very High Resolution X-Ray Computed Tomography (VHR-CT) to "digitally dissect" a 53-million-year-old male spider fossilized in amber from the Paris Basin in France (1st image). The technique reveals the preservation of the internal organs. "Amber provides a unique window into past forest ecosystems. It retains an incredible amount of information, not just about the spiders themselves, but also about the environment in which they lived,"says specialist Dr. David Penney.
• A doctoral student in paleontology at Imperial College London used a CT-scanner to obtain detailed 3-dimensional images of a 310 million-year-old ancestral cockroach fossil embedded in iron carbonate from the U.K. Midlands (3rd image). The scans offer glimpses of the wings, mandibles, legs, and antennae of this 3cm insect that have never been seen before. "This is now one of the best known roach fossils from this age and we can make educated guesses about how it lived," says Russell Garwood, who has deduced that it could sweep its antennae in an arc, climb trees to lay its eggs, and run very fast.
• Lee Berger, a paleoanthropologist at the University of the Witwatersrand in South Africa has subjected 2 Australopithecus fossils to X-ray synchrotron microtomography. The technology allows the scientists to examine even some of the soft tissue of the hominid skeletons without taking them out of their original matrix. "We have done things like CAT-scan these…creating remarkable images that have allowed us to leave part of the evidence for future generations of science, like the rock attached to it. We can eliminate that rock now with science, by making it invisible....We can thus peer inside of places that normally might have been damaged. We can put the pieces back together and you can now look into the face of a skull 1.9 millions years ago, many parts of [which] have never been touched by a preparation tool...something that could not be done before," explains Berger.
• Scientists from the University of Rennes are using a synchrotron x-ray imaging technique known as propagation phase contrast microradiography to visualize animal inclusions in opaque amber from mid-Cretaceous sites of the Charentes region in France. These include wasps, flies, ants (2nd image), spiders, and dinosaur feathers. “Researchers have tried to study this kind of amber for many years with little or no success. This is the first time that we can actually discover and study the fossils contained within," says paleontologist Paul Tafforeau.
• An international team of scientists have applied synchrotron-radiation x-ray tomographic microscopy to the study of the embryology of 500-million-year-old worms from Middle to Late Cambrian fossil beds in Hunan, China. "SRXTM provides a method of non-invasive analysis that rivals the resolution achieved even by destructive methods, probing the very limits of fossilization and providing insight into embryology during the emergence of metazoan phyla," reads their letter to Nature.
• Synchotron x-rays are being used by researchers at Stanford University in California, where the Thermopolis archaeopteryx fossil was recently scanned to reveal additional details about its soft tissue. This method, which involves a particle accelerator, can even illuminate specific chemical elements. "These X-rays work a thousand times better than what you could do with a commercial X-ray machine – only a synchrotron can do this," says Stanford's Uwe Bergmann.

As it turns out, this post was entirely appropriate for today, because I had an MRI of my brain done for my neurologist this afternoon. I confirmed with the technician that helium is used in the maintenance as well as the production of the machine, and she was well aware of the looming shortage.