tag:theconversation.com,2011:/au/topics/ct-scan-3157/articlesCT scan – The Conversation2024-02-06T06:13:31Ztag:theconversation.com,2011:article/2226322024-02-06T06:13:31Z2024-02-06T06:13:31ZNewly identified prehistoric pterosaur will help us understand evolution of flying reptiles<figure><img src="https://images.theconversation.com/files/573093/original/file-20240202-19-jahq7z.jpg?ixlib=rb-1.1.0&rect=0%2C13%2C2246%2C1232&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">An artist's impression of the new pterosaur species, Cheoptera </span> <span class="attribution"><span class="source">Mark Witton/Natural History Museum</span>, <span class="license">Author provided</span></span></figcaption></figure><p>When dinosaurs roamed the land, the skies above their heads were filled with a variety of soaring reptiles, which swept through the air on <a href="https://www.scientificamerican.com/article/pterosaurs-were-monsters-of-the-mesozoic-skies/">slender, membranous wings</a>. These animals, pterosaurs, were not dinosaurs but their <a href="https://www.nhm.ac.uk/discover/watch-a-pterosaur-fly.html">evolutionary cousins</a>. </p>
<p><a href="https://www.tandfonline.com/doi/full/10.1080/02724634.2023.2298741">We’ve just announced</a> the discovery of a new species of pterosaur nearly 15 years after a fossil was found on the Isle of Skye. It is one of the most complete pterosaur fossils to be found in the UK since palaeontologist <a href="https://www.nhm.ac.uk/discover/mary-anning-unsung-hero.html">Mary Anning</a> unearthed <a href="https://www.geolsoc.org.uk/Library-and-Information-Services/Collection-Highlights/Mary-Anning-and-the-Geological-Society/pterosaurs-coprolites-and-sepia/dimorphodon-macronyx">the first</a> from the Dorset coast in 1828. </p>
<p>Pterosaurs were the first backboned animals to achieve powered flight (<a href="https://www.sciencedirect.com/science/article/pii/S0960982216314610">insects got there</a> first). Pterosaur fossils are known worldwide but their remains are rare in comparison to those of their land and water-based relatives. This is due to the <a href="https://theconversation.com/pterosaurs-should-%20have-been-too-big-to-fly-so-how-did-they-manage-it-60892">fragile nature of their skeletons</a>, which are composed of thin-walled, hollow bones.</p>
<p>Pterosaur fossils are often incomplete, <a href="https://www.amnh.org/exhibitions/pterosaurs-flight-in-the-age-of-dinosaurs/why-are-pterosaur-fossils-rare">crushed and distorted</a>. A sparse pterosaur record has been harvested from the Jurassic period (200-145 million years ago) and <a href="https://www.nhm.ac.uk/discover/the-cretaceous-period.html#:%7E:text=When%20was%20the%20Cretaceous%20Period,Cenozoic%20Era%2C%20our%20current%20era.">Cretaceous period</a> (145-66 million years ago) rocks of the UK since Anning’s discoveries. </p>
<p>But most of these are limited to a few isolated bones <a href="https://www.southampton.ac.uk/oes/news/2013/03/20_new_pterosaur_from_isle_of_wight.page">such as <em>Vectidraco</em></a>, a toothless pterosaur whose fossilised remains were found on the Isle of Wight in 2008 by five-year-old Daisy Morris. </p>
<p>This is where <a href="https://www.scottishtours.co.uk/scotland/isle-of-skye/">the Isle of Skye</a> comes in. Although Skye is most famous for the ancient volcanic landscapes of the <a href="https://www.isleofskye.com/skye-guide/skye-places/the-cuillin">Cuillin Hills</a> mountain range, there are <a href="https://www.isleofskye.com/skye-guide/history/jurassic-skye#:%7E:text=The%20Isle%20of%20Skye%20holds,mainly%20contained%20in%20local%20knowledge.">Jurassic-aged rocks</a> around the margins of the island. </p>
<p>Over the past 50 years teams of geologists and palaeontologists have been gradually uncovering <a href="https://www.cambridge.org/core/journals/earth-and-environmental-science-transactions-of-royal-society-of-edinburgh/article/diverse-vertebrate-assemblage-of-the-kilmaluag-formation-bathonian-middle-jurassic-of-skye-scotland/B8DD4D46839FA83FA2E57437BDEBF2B8">more of Skye’s ancient</a> past. This work has accelerated thanks to the new imaging techniques, mainly CT scanning, which <a href="https://www.theguardian.com/science/2016/mar/30/getting-under-a-fossils-skin-how-ct-scans-have-changed-palaeontology-dinosaur-lizard">make it easier</a> to study these fossils. </p>
<p>Our new pterosaur was found in 2006 by a team of researchers including Paul Barrett in a loose boulder lying on the beach at <a href="https://canmore.org.uk/site/138335/cladach-a-ghlinne">Cladach a’Glinne</a>, on the edge of a remote bay overshadowed by the Cuillins. </p>
<p>At first sight, the new skeleton was an underwhelming smear of thin, broken, black bone set in a hard, dark-grey mudstone. But, even then, these thin bones suggested that the find would turn out to be interesting.</p>
<p>It took <a href="https://www.nhm.ac.uk/our-science/departments-and-staff/staff-directory/lu-allington-jones.html">Lu Allington-Jones</a>, one of the Natural History Museum’s fossil technicians, nearly two years to prepare our discovery for study. The rocks from Skye are extremely hard, and the fossil bones are delicate. </p>
<p>Although Lu’s work allowed us to study some of the bones, others remained encased in rock as they were too dainty to remove or expose further.</p>
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<a href="https://images.theconversation.com/files/573095/original/file-20240202-21-y3x46f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/573095/original/file-20240202-21-y3x46f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/573095/original/file-20240202-21-y3x46f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=469&fit=crop&dpr=1 600w, https://images.theconversation.com/files/573095/original/file-20240202-21-y3x46f.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=469&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/573095/original/file-20240202-21-y3x46f.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=469&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/573095/original/file-20240202-21-y3x46f.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=589&fit=crop&dpr=1 754w, https://images.theconversation.com/files/573095/original/file-20240202-21-y3x46f.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=589&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/573095/original/file-20240202-21-y3x46f.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=589&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Skeleton of the new pterosaur <em>Ceoptera evansae</em> from the Isle of Skye.</span>
<span class="attribution"><span class="source">The Trustees of the Natural History Museum</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
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<p>Once this work was complete, the specimen lay dormant in the museum’s collections for about nine years. But then we decided to examine the fossil using the <a href="https://www.bristol.ac.uk/earthsciences/research/palaeobiology/facilities/xtm-facility/">university’s CT scanner</a>. </p>
<p>Using this equipment, similar to that used in a hospital for diagnosing broken bones, with many months of careful imaging we were able to reveal almost the entire animal in three dimensions. </p>
<p>After comparing it with other pterosaur fossils from around the world, we realised that we were dealing with something new and we called it <em>Ceoptera evansae</em> (from the Gaelic name for Skye, Eilean a’ Cheò, Isle of Mist, and honouring <a href="https://profiles.ucl.ac.uk/9226-susan-evans">Professor Susan Evans</a> who has worked extensively in the area). </p>
<p>This pterosaur species is important because of the quality of preservation and its age. It is one of only a <a href="https://epub.ub.uni-muenchen.de/12007/1/zitteliana_2008_b28_05.pdf">handful of pterosaur skeletons</a> from the <a href="https://www.nationalgeographic.com/science/article/jurassic">Middle Jurassic period</a>, approximately 167 million years ago. </p>
<p>At this time pterosaurs were undergoing colossal anatomical changes from early small-bodied, long-tailed pterosaurs such as <em><a href="https://www.britannica.com/animal/Dimorphodon">Dimorphodon</a></em> (roughly the size of a raven) to later pterosaurs like <em><a href="https://www.britannica.com/animal/Pteranodon">Pteranodon</a></em> which had a wingspan similar to that of a small airplane. </p>
<p>The lack of good pterosaur specimens from this time interval has hindered scientists’ attempts to understand how pterosaurs evolved from these earlier forms to those that dominated the skies later in Earth’s history. <em>Ceoptera</em> helps to fill this a gap. </p>
<p>For 15 years scientists have studied <a href="https://www.smithsonianmag.com/science-%20nature/darwinopterus-a-transitional-pterosaur-55145586/">transitional pterosaurs</a> that show a mix of features seen in the
earlier, tailed forms and their later, giant relatives. <em>Ceoptera</em> is one of these transitional forms (called a <a href="https://www.smithsonianmag.com/science-nature/darwinopterus-a-transitional-pterosaur-55145586/">Darwinopteran</a>), one of the first members of this group known from Europe, and is the second-oldest darwinopteran worldwide. </p>
<p>This makes <em>Ceoptera</em> crucial in understanding the pace of pterosaur evolution, and it has pushed back the appearance of more advanced pterosaurs to the Early Jurassic period, about 10 million years earlier than previously thought. It brings us one step closer to understanding where and when the more advanced pterosaurs evolved. </p>
<p><em>Ceoptera</em>‘s discovery shows how palaeontologists are making new discoveries all the time, even in places like the UK - one of the most heavily surveyed places worldwide. It also shows how new technology can is helping to unearth the mysteries of Earth’s ancient past. </p>
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<p class="fine-print"><em><span>Paul Barrett is affiliated with The Linnean Society (Trustee).</span></em></p><p class="fine-print"><em><span>Elizabeth Martin-Silverstone does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>The Isle of Skye has a rich palaeontological heritage, so perhaps it’s no surprise scientists made an important discovery there.Elizabeth Martin-Silverstone, Research Assistant in Palaeontology, University of BristolPaul Barrett, Individual Merit Researcher, Natural History MuseumLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1861162022-07-20T15:03:08Z2022-07-20T15:03:08ZMeet Qikiqtania, a fossil fish with the good sense to stay in the water while others ventured onto land<figure><img src="https://images.theconversation.com/files/474947/original/file-20220719-12-fg9agl.jpg?ixlib=rb-1.1.0&rect=4%2C350%2C2686%2C1847&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">An artist's vision of *Qikiqtania* enjoying its fully aquatic, free-swimming lifestyle.</span> <span class="attribution"><span class="source">Alex Boersma</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span></figcaption></figure><p>Approximately 365 million years ago, one group of fishes left the water to live on land. These animals were early <a href="https://ucmp.berkeley.edu/vertebrates/tetrapods/tetraintro.html">tetrapods</a>, a lineage that would radiate to include many thousands of species including amphibians, birds, lizards and mammals. Human beings are descendants of those early tetrapods, and we share the legacy of their water-to-land transition.</p>
<p>But what if, instead of venturing onto the shores, they had turned back? What if these animals, just at the cusp of leaving the water, had receded to live again in more open waters?</p>
<p><a href="https://www.nature.com/articles/s41586-022-04990-w">A new fossil</a> suggests that one fish, in fact, did just that. In contrast to other closely related animals, which were using their fins to prop their bodies up on the bottom of the water and perhaps occasionally venturing out onto land, this newly discovered creature had fins that were built for swimming.</p>
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<span class="caption">Tom Stewart holds the <em>Qikiqtania</em> fossil.</span>
<span class="attribution"><span class="source">Stephanie Sang</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
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<p>In March 2020, I was at The University of Chicago and a member of biologist <a href="https://oba.bsd.uchicago.edu/faculty/neil-h-shubin-phd">Neil Shubin’s</a> lab. I was working with Justin Lemberg, another researcher in our group, to process a fossil that was collected back in 2004 during an expedition to the Canadian Arctic.</p>
<p>From the surface of the rock it was embedded in, we could see fragments of the jaws, about 2 inches long (5 cm) and with pointed teeth. There were also patches of white scales with bumpy texture. The anatomy gave us subtle hints that the fossil was an early tetrapod. But we wanted to see inside the rock.</p>
<p>So we used a technology called CT scanning, which shoots X-rays through the specimen, to look for anything that might be hidden within, out of view. On March 13, we scanned an unassuming piece of rock that had a few scales on top and discovered it contained a complete fin buried inside. Our jaws dropped. A few days later, the lab and campus shut down, and COVID-19 sent us into lockdown.</p>
<h2>The fin revealed</h2>
<p>A fin like this is extremely precious. It can give scientists clues into how early tetrapods were evolving and how they were living hundreds of millions of years ago. For example, based on the shape of certain bones in the skeleton, we can make predictions about whether an animal was swimming or walking. </p>
<p>Although that first scan of the fin was promising, we needed to see the skeleton in high resolution. As soon as we were allowed back on campus, a professor in the university’s department of the geophysical sciences helped us to trim down the block using a rock saw. This made the block more fin, less rock, allowing for a better scan and a closer view of the fin.</p>
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<figcaption><span class="caption">An animation of the pectoral fin of <em>Qikiqtania</em> showing how it was preserved in the rock. Scales are shown in yellow, fin rays in blue, and the endoskeleton in grey. <em>Credit: Tom Stewart</em></span></figcaption>
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<p>When the dust had cleared and we’d finished analyzing data on the jaws, scales and fin, we realized that this animal was a new species. Not only that, it turns out that this is one of the closest known relatives to limbed vertebrates – those creatures with fingers and toes.</p>
<p>We named it <em>Qikiqtania wakei</em>. Its genus name, pronounced “kick-kiq-tani-ahh,” refers to the Inuktitut words Qikiqtaaluk or Qikiqtani, the traditional name for the <a href="https://en.wikipedia.org/wiki/Qikiqtaaluk_Region">region where the fossil was found</a>. When this fish was alive, many hundreds of millions of years ago, this was a warm environment with rivers and streams. Its species name honors the late <a href="https://www.nytimes.com/2021/05/19/science/david-wake-dead.html">David Wake</a>, a scientist and mentor who inspired so many of us in the field of evolutionary and developmental biology.</p>
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<figcaption><span class="caption">An animation of the full skeleton of <em>Qikiqtania</em>. <em>Credit: Tom Stewart</em></span></figcaption>
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<h2>Skeletons tell how an animal lived</h2>
<p><em>Qikiqtania</em> reveals a lot about a critical period in our lineage’s history. Its scales tell researchers unambiguously that it was living underwater. They show sensory canals that would have allowed the animal to detect the flow of water around its body. Its jaws tell us that it was foraging as a predator, biting and holding onto prey with a series of fangs and drawing food into its mouth by suction.</p>
<p>But it is <em>Qikiqtania</em>’s pectoral fin that is most surprising. It has a humerus bone, just as our upper arm does. But <em>Qikiqtania</em>’s has a very peculiar shape.</p>
<p>Early tetrapods, like <a href="https://shubinlab.uchicago.edu/research-2-2/"><em>Tiktaalik</em></a>, have humeri that possess a prominent ridge on the underside and a characteristic set of bumps, where muscles attach. These bony bumps tell us that early tetrapods were living on the bottom of lakes and streams, using their fins or arms to prop themselves up, first on the ground underwater and later on land.</p>
<p><em>Qikiqtania</em>’s humerus is different. It lacks those trademark ridges and processes. Instead, its humerus is thin and boomerang-shaped, and the rest of the fin is large and paddle-like. This fin was built for swimming.</p>
<p>Whereas other early tetrapods were playing at the water’s edge, learning what land had to offer, <em>Qikiqtania</em> was doing something different. Its humerus is truly unlike any others known. My colleagues and I think it shows that <em>Qikiqtania</em> had turned back from the water’s edge and evolved to live, once again, off the ground and in open water.</p>
<h2>Evolution isn’t a march in one direction</h2>
<p><a href="https://plato.stanford.edu/entries/evolution/">Evolution isn’t a simple, linear process</a>. Although it might seem like early tetrapods were trending inevitably toward life on land, <em>Qikiqtania</em> shows exactly the limitations of such a directional perspective. Evolution didn’t build a ladder towards humans. It’s a complex set of processes that together grow the tangled tree of life. New species form and they diversify. Branches can head off in any number of directions.</p>
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<span class="caption">Neil Shubin, who found the fossil, pointing across the valley to the site where <em>Qikiqtania</em> was discovered on Ellesmere Island.</span>
<span class="attribution"><span class="source">Neil Shubin</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
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<p>This fossil is special for so many reasons. It’s not just miraculous that this fish was preserved in rock for hundreds of millions of years before being discovered by scientists in the Arctic, on <a href="https://en.wikipedia.org/wiki/Ellesmere_Island">Ellesmere Island</a>. It’s not just that it’s remarkably complete, with its full anatomy revealed by serendipity at the cusp of a global pandemic. It also provides, for the first time, a glimpse of the broader diversity and range of lifestyles of fishes at the water-to-land transition. It helps researchers see more than a ladder and understand that fascinating, tangled tree.</p>
<h2>Discoveries depend on community</h2>
<p><em>Qikiqtania</em> was found on Inuit land, and it belongs to that community. My colleagues and I were only able to conduct this research because of the generosity and support of individuals in the hamlets of Resolute Bay and Grise Fiord, the Iviq Hunters and Trappers of Grise Fiord, and the Department of Heritage and Culture, Nunavut. To them, on behalf of our entire research team, “nakurmiik.” Thank you. Paleontological expeditions onto their land have truly changed how we understand the history of life on Earth.</p>
<p>COVID-19 kept many paleontologists from traveling and visiting field sites across the world these last few years. We’re eager to return, to visit with old friends and to search again. Who knows what other animals lie hidden, waiting to be discovered inside blocks of unassuming stone.</p><img src="https://counter.theconversation.com/content/186116/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Thomas Stewart does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>The newly discovered species – Qikiqtania – highlights evolution’s twisty, tangled path.Thomas Stewart, Assistant Professor of Biology, Penn StateLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1499072021-09-30T12:29:56Z2021-09-30T12:29:56Z50 years ago, the first CT scan let doctors see inside a living skull – thanks to an eccentric engineer at the Beatles’ record company<figure><img src="https://images.theconversation.com/files/423940/original/file-20210929-26-mhu7qn.jpg?ixlib=rb-1.1.0&rect=55%2C0%2C4034%2C2996&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Godfrey Hounsfield stands beside the EMI-Scanner in 1972.</span> <span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/the-25-000-macrobert-award-and-gold-medal-were-presented-by-news-photo/828266748"> PA Images via Getty Images</a></span></figcaption></figure><p>The possibility of precious objects hidden in secret chambers can really ignite the imagination. In the mid-1960s, <a href="https://doi.org/10.4103/0972-2327.194414">British engineer Godfrey Hounsfield</a> pondered whether one could detect hidden areas in Egyptian pyramids by capturing cosmic rays that passed through unseen voids.</p>
<p>He held onto this idea over the years, which can be paraphrased as “<a href="https://birorgukportal.force.com/CPBase__item?id=a0j20000006wvWqAAI">looking inside a box without opening it</a>.” Ultimately he did figure how to use high-energy rays to reveal what’s invisible to the naked eye. He invented a way to see inside the hard skull and get a picture of the soft brain inside.</p>
<p>The first computed tomography image – a CT scan – of the human brain was made 50 years ago, on Oct. 1, 1971. Hounsfield never made it to Egypt, but his invention did take him to Stockholm and Buckingham Palace.</p>
<h2>An engineer’s innovation</h2>
<p>Godfrey Hounsfield’s early life did not suggest that he would accomplish much at all. He was not a particularly good student. As a young boy his teachers <a href="https://www.worldcat.org/title/godfrey-hounsfield-intuitive-genius-of-ct/oclc/823708300&referer=brief_results">described him as “thick</a>.”</p>
<p>He joined the British Royal Air Force at the start of the Second World War, but he wasn’t much of a soldier. He was, however, a wizard with electrical machinery – especially the <a href="https://www.iwm.org.uk/history/how-radar-changed-the-second-world-war">newly invented radar</a> that he would jury-rig to help pilots better find their way home on dark, cloudy nights.</p>
<p>After the war, Hounsfield followed his commander’s advice and got a degree in engineering. He practiced his trade at EMI – the company would become <a href="https://doi.org/10.1097/RCT.0b013e318249416f">better known for selling Beatles albums</a>, but started out as Electric and Music Industries, with a focus on electronics and electrical engineering.</p>
<p>Hounsfield’s natural talents propelled him to lead the team building the most advanced mainframe computer available in Britain. But by the ‘60s, EMI wanted out of the competitive computer market and wasn’t sure what to do with the brilliant, eccentric engineer.</p>
<p>While on a forced holiday to ponder his future and what he might do for the company, Hounsfield met a physician who complained about the poor quality of X-rays of the brain. <a href="https://www.medmuseum.siemens-healthineers.com/en/stories-from-the-museum/our-brain?">Plain X-rays show marvelous details of bones</a>, but the brain is an amorphous blob of tissue – on an X-ray it all looks like fog. This got Hounsfield thinking about his old idea of finding hidden structures without opening the box.</p>
<h2>A new approach reveals the previously unseen</h2>
<p>Hounsfield formulated a new way to approach the problem of imaging what’s inside the skull.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/423821/original/file-20210929-18-8ywyce.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="schematic of three X-ray beams through one 'slice' of brain" src="https://images.theconversation.com/files/423821/original/file-20210929-18-8ywyce.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/423821/original/file-20210929-18-8ywyce.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=567&fit=crop&dpr=1 600w, https://images.theconversation.com/files/423821/original/file-20210929-18-8ywyce.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=567&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/423821/original/file-20210929-18-8ywyce.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=567&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/423821/original/file-20210929-18-8ywyce.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=712&fit=crop&dpr=1 754w, https://images.theconversation.com/files/423821/original/file-20210929-18-8ywyce.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=712&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/423821/original/file-20210929-18-8ywyce.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=712&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">X-rays beam through each ‘slice’ of brain, oriented at each degree from 1 to 180 in a semicircle.</span>
<span class="attribution"><span class="source">Edmund S. Higgins</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>First, he would conceptually <a href="https://doi.org/10.1259/0007-1285-46-552-1016">divide the brain into consecutive slices</a> – like a loaf of bread. Then he planned to beam a series of X-rays through each layer, repeating this for each degree of a half-circle. The strength of each beam would be captured on the opposite side of the brain – with stronger beams indicating they’d traveled through less dense material.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/423822/original/file-20210929-24-lb50bz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="simplified illustration of more X-rays making it through softer material" src="https://images.theconversation.com/files/423822/original/file-20210929-24-lb50bz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/423822/original/file-20210929-24-lb50bz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=365&fit=crop&dpr=1 600w, https://images.theconversation.com/files/423822/original/file-20210929-24-lb50bz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=365&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/423822/original/file-20210929-24-lb50bz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=365&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/423822/original/file-20210929-24-lb50bz.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=458&fit=crop&dpr=1 754w, https://images.theconversation.com/files/423822/original/file-20210929-24-lb50bz.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=458&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/423822/original/file-20210929-24-lb50bz.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=458&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Calculating the strength of each X-ray once it’s passed through the object, and working backward with an impressive algorithm, it is possible to construct an image.</span>
<span class="attribution"><span class="source">Edmund S. Higgins</span>, <a class="license" href="http://creativecommons.org/licenses/by-nd/4.0/">CC BY-ND</a></span>
</figcaption>
</figure>
<p>Finally, in possibly his most ingenious invention, Hounsfield created an algorithm to reconstruct an image of the brain based on all these layers. By working backward and using one of the era’s fastest new computers, he could calculate the value for each little box of each brain layer. Eureka!</p>
<p>But there was a problem: EMI wasn’t involved in the medical market and had no desire to jump in. The company allowed Hounsfield to work on his product, but with scant funding. He was forced to scrounge through the scrap bin of the research facilities and cobbled together a primitive scanning machine - small enough to rest atop a dining table.</p>
<p>Even with <a href="https://doi.org/10.1259/0007-1285-49-583-604">successful scans of inanimate objects</a> and, later, <a href="https://www.jweekly.com/1997/04/25/kosher-cow-brains-help-pioneer-ct-scan-technology/">kosher cow brains</a>, the powers that be at EMI remained underwhelmed. Hounsfield needed to find outside funding if he wanted to proceed with a human scanner. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/423636/original/file-20210928-14-96ensy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="line drawing of CT scanner" src="https://images.theconversation.com/files/423636/original/file-20210928-14-96ensy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/423636/original/file-20210928-14-96ensy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=786&fit=crop&dpr=1 600w, https://images.theconversation.com/files/423636/original/file-20210928-14-96ensy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=786&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/423636/original/file-20210928-14-96ensy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=786&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/423636/original/file-20210928-14-96ensy.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=988&fit=crop&dpr=1 754w, https://images.theconversation.com/files/423636/original/file-20210928-14-96ensy.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=988&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/423636/original/file-20210928-14-96ensy.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=988&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Schematic diagram of the CT scanner included in Hounsfield’s U.S. patent.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:CT_US4115698_Fig1.jpg">Godfrey Newbold Hounsfield</a></span>
</figcaption>
</figure>
<p>Hounsfield was a brilliant, intuitive inventor, but not an effective communicator. Luckily he had a sympathetic boss, Bill Ingham, who saw the value in Hounsfield’s proposal and struggled with EMI to keep the project afloat. </p>
<p>He knew there were no grants they could obtain quickly, but reasoned the U.K. Department of Health and Social Security could purchase equipment for hospitals. Miraculously, Ingham sold them four scanners before they were even built. So, Hounsfield organized a team, and they raced to build a safe and effective human scanner. </p>
<p>Meanwhile, Hounsfield needed patients to try out his machine on. He found a somewhat reluctant neurologist who agreed to help. The team installed a full-sized scanner at the <a href="http://www.impactscan.org/CThistory.htm?">Atkinson Morley Hospital in London</a>, and on Oct. 1, 1971, they scanned their first patient: a middle-aged woman who showed signs of a brain tumor.</p>
<p><a href="https://doi.org/10.1259/bjr/29444122">It was not a fast process</a> – 30 minutes for the scan, a drive across town with the magnetic tapes, 2.5 hours processing the data on an EMI mainframe computer and capturing the image with a Polaroid camera before racing back to the hospital.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/423942/original/file-20210929-64926-b3svf8.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="pixelated image of a brain" src="https://images.theconversation.com/files/423942/original/file-20210929-64926-b3svf8.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/423942/original/file-20210929-64926-b3svf8.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=530&fit=crop&dpr=1 600w, https://images.theconversation.com/files/423942/original/file-20210929-64926-b3svf8.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=530&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/423942/original/file-20210929-64926-b3svf8.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=530&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/423942/original/file-20210929-64926-b3svf8.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=665&fit=crop&dpr=1 754w, https://images.theconversation.com/files/423942/original/file-20210929-64926-b3svf8.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=665&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/423942/original/file-20210929-64926-b3svf8.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=665&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The first clinical CT scan, with brain tumor visible as darker blob.</span>
<span class="attribution"><a class="source" href="https://www.ncbi.nlm.nih.gov/books/NBK546157/figure/ch8.fig2/">'Medical Imaging Systems: An Introductory Guide,' Maier A, Steidl S, Christlein V, et al., editors.</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>And there it was – in her left frontal lobe – a cystic mass about the size of a plum. With that, every other method of imaging the brain was obsolete.</p>
<h2>Millions of CT scans every year</h2>
<p>EMI, with no experience in the medical market, suddenly held a monopoly for a machine in high demand. It jumped into production and was initially very successful at selling the scanners. But within five years, bigger, more experienced companies with more research capacity such as GE and Siemens were producing better scanners and gobbling up sales. EMI eventually exited the medical market – and <a href="https://www.blackwellpublishing.com/content/GrantContemporaryStrategyAnalysis/docs/Grant_Cases_Guide_Chapter_10.pdf">became a case study</a> in why it can be better to partner with one of the big guys instead of trying to go it alone.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/423941/original/file-20210929-66198-1pskqvw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="Hounsfield in tuxedo shaking hands with King facing away from camera" src="https://images.theconversation.com/files/423941/original/file-20210929-66198-1pskqvw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/423941/original/file-20210929-66198-1pskqvw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=641&fit=crop&dpr=1 600w, https://images.theconversation.com/files/423941/original/file-20210929-66198-1pskqvw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=641&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/423941/original/file-20210929-66198-1pskqvw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=641&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/423941/original/file-20210929-66198-1pskqvw.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=805&fit=crop&dpr=1 754w, https://images.theconversation.com/files/423941/original/file-20210929-66198-1pskqvw.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=805&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/423941/original/file-20210929-66198-1pskqvw.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=805&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">King Carl Gustaf awards the Nobel Prize to Hounsfield in Stockholm on Dec. 11, 1979.</span>
<span class="attribution"><a class="source" href="https://www.gettyimages.com/detail/news-photo/british-scientist-sir-godfrey-hounsfield-joint-nobel-news-photo/51867039">Keystone/Hulton Archive via Getty Images</a></span>
</figcaption>
</figure>
<p>Hounsfield’s innovation transformed medicine. He <a href="https://www.nobelprize.org/prizes/medicine/1979/press-release/">shared the Nobel Prize</a> for Physiology or Medicine in 1979 and was knighted by the Queen in 1981. He continued to putter around with inventions until his final days in 2004, when he died at 84. </p>
<p>In 1973, American <a href="https://doi.org/10.1197/jamia.M2127">Robert Ledley</a> developed <a href="https://doi.org/10.1126/science.186.4160.207">a whole-body scanner</a> that could image other organs, blood vessels and, of course, bones. Modern scanners are faster, provide better resolution, and most important, do it with less radiation exposure. There are even mobile scanners.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/423640/original/file-20210928-26-3rul6h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/423640/original/file-20210928-26-3rul6h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/423640/original/file-20210928-26-3rul6h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/423640/original/file-20210928-26-3rul6h.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/423640/original/file-20210928-26-3rul6h.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/423640/original/file-20210928-26-3rul6h.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/423640/original/file-20210928-26-3rul6h.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/423640/original/file-20210928-26-3rul6h.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Modern CT scans provide much higher resolution images of the ‘slices’ of the brain than Hounsfield’s original scan did in 1971.</span>
</figcaption>
</figure>
<p>By 2020, technicians were performing <a href="https://www.sciencedaily.com/releases/2020/07/200723115909.htm">more than 80 million scans annually in the U.S.</a>. Some physicians argue that number is excessive and maybe a third are unnecessary. While that may be true, the CT scan has <a href="https://www.fda.gov/radiation-emitting-products/medical-x-ray-imaging/computed-tomography-ct">benefited the health</a> of many patients around the world, helping identify tumors and determine if surgery is needed. They’re particularly useful for a quick search for internal injuries after accidents in the ER.</p>
<p>And remember Hounsfield’s idea about the pyramids? In 1970 scientists placed <a href="https://en.wikipedia.org/wiki/Cosmic-ray_observatory">cosmic ray detectors</a> in the lowest chamber in the Pyramid of Khafre. They concluded that <a href="https://doi.org/10.1126/science.167.3919.832">no hidden chamber was present within the pyramid</a>. In 2017, another team placed cosmic ray detectors in the Great Pyramid of Giza and <a href="https://doi.org/10.1038/nature.2017.22939">found a hidden, but inaccessible, chamber</a>. It’s unlikely it will be explored anytime soon. </p>
<p><em>This article has been updated to correct the spelling of the name of Hounsfield’s boss at EMI, Bill Ingham.</em></p>
<p>[<em>You’re smart and curious about the world. So are The Conversation’s authors and editors.</em> <a href="https://theconversation.com/us/newsletters/the-daily-3?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=youresmart">You can read us daily by subscribing to our newsletter</a>.]</p><img src="https://counter.theconversation.com/content/149907/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Edmund S. Higgins does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>On Oct. 1, 1971, Godfrey Hounsfield’s invention took its first pictures of a human brain, using X-rays and an ingenious algorithm to identify a woman’s tumor from outside of her skull.Edmund S. Higgins, Affiliate Associate Professor of Psychiatry & Family Medicine, Medical University of South CarolinaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/909062018-03-20T10:42:20Z2018-03-20T10:42:20ZOn his 250th birthday, Joseph Fourier’s math still makes a difference<figure><img src="https://images.theconversation.com/files/210406/original/file-20180314-113479-1gr7sz8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Fourier's name is inscribed on the Eiffel Tower.</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/philmciver/1018062764">philmciver/flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span></figcaption></figure><p>March 21 marks the 250th birthday of one of the most influential
mathematicians in history. He accompanied Napoleon on
his expedition to Egypt, revolutionized science’s understanding of
heat transfer, developed the mathematical tools used today to create
CT and MRI scan images, and discovered the greenhouse effect.</p>
<p>His name was Joseph Fourier. He <a href="https://ebooks.adelaide.edu.au/f/fourier/joseph/heat/preliminary.pdf">wrote</a> of mathematics: “There cannot be a language more universal and more simple, more free from errors and obscurities … Mathematical analysis is as extensive as nature itself, and it defines all perceptible relations.” Fourier’s work continues to shape life today, especially for people like ourselves working in fields such as mathematics and radiology.</p>
<h2>Fourier’s life</h2>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/210404/original/file-20180314-113465-aqizfg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/210404/original/file-20180314-113465-aqizfg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/210404/original/file-20180314-113465-aqizfg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=734&fit=crop&dpr=1 600w, https://images.theconversation.com/files/210404/original/file-20180314-113465-aqizfg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=734&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/210404/original/file-20180314-113465-aqizfg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=734&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/210404/original/file-20180314-113465-aqizfg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=923&fit=crop&dpr=1 754w, https://images.theconversation.com/files/210404/original/file-20180314-113465-aqizfg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=923&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/210404/original/file-20180314-113465-aqizfg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=923&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Mathematician and physicist Joseph Fourier.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File:Fourier2.jpg">Wikimedia Commons</a></span>
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</figure>
<p>As a <a href="http://www-groups.dcs.st-and.ac.uk/history/Biographies/Fourier.html">troubled orphan</a> in France, Fourier was transformed by his first encounter with mathematics. Thanks to a local bishop who recognized his talent, Fourier received an education through Benedictine monks. As a college student, he so loved math that he collected discarded candle stumps so he could continue his studies after others had gone to bed.</p>
<p>As a young man, Fourier was soon swept up by the French Revolution. However, he became disenchanted by its excessive brutality, and his protests landed him in prison for part of 1794. After his release, he was appointed to the faculty of an engineering school. There he proved his genius by substituting for ill colleagues, teaching subjects ranging from physics to classics.</p>
<p>Traveling with Napoleon to Egypt in 1798, Fourier was appointed secretary of the <a href="https://napoleon.lindahall.org/institute_of_egypt.shtml">Egyptian Institute</a>, which Napoleon modeled on the Institute of France. When the British fleet stranded the French forces, he organized the manufacture of weapons and munitions to permit the French to continue fighting. Fourier returned to France after the British navy forced the French to surrender. Even in the midst of such difficult circumstances, he managed to publish a number of mathematical papers. </p>
<h2>Heat transfer</h2>
<p>One of the most important fruits of Fourier’s studies concerns heat. </p>
<p><a href="http://www.thermopedia.com/content/781/">Fourier’s law</a> states that heat transfers through a material at a rate proportional to both the difference in temperature between different areas and to the area across which the transfer takes place. For example, people who are overheated can cool off quickly by getting to a cool place and exposing as much of their body to it as possible.</p>
<p>Fourier’s work enables scientists to predict the future distribution of heat. Heat is transferred through different materials at different rates. For example, brass has a high <a href="https://www.engineeringtoolbox.com/thermal-conductivity-d_429.html">thermal conductivity</a>. Air is poorly conductive, which is why it’s frequently used in insulation.</p>
<p>Remarkably, Fourier’s equation applies widely to matter, whether in the form of solid, liquid or gas. It powerfully shaped scientists’ understanding of both electricity and the process of diffusion. It also <a href="http://onlinelibrary.wiley.com/doi/10.1029/1998RG900006/full">transformed</a> scientists’ understanding of flow in nature generally – from water’s passage through porous rocks to the movement of blood through capillaries.</p>
<h2>Fourier transform and CT</h2>
<p>Today, when helping to care for patients, radiologists rely on another mathematical discovery of Fourier’s, now referred to as the “Fourier transform.”</p>
<p>In <a href="http://www.dspguide.com/ch25/5.htm">CT scans</a>, doctors send X-ray beams through a patient from multiple different directions. Some X-rays emerge from the other side, where they can be measured, while others are blocked by structures within the body.</p>
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<a href="https://images.theconversation.com/files/209937/original/file-20180312-30979-ljnc5k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/209937/original/file-20180312-30979-ljnc5k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/209937/original/file-20180312-30979-ljnc5k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=400&fit=crop&dpr=1 600w, https://images.theconversation.com/files/209937/original/file-20180312-30979-ljnc5k.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=400&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/209937/original/file-20180312-30979-ljnc5k.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=400&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/209937/original/file-20180312-30979-ljnc5k.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=503&fit=crop&dpr=1 754w, https://images.theconversation.com/files/209937/original/file-20180312-30979-ljnc5k.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=503&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/209937/original/file-20180312-30979-ljnc5k.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=503&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Modern medical imaging machines rely on Fourier’s transform.</span>
<span class="attribution"><span class="source">zlikovec/shutterstock.com</span></span>
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</figure>
<p>With many such measurements taken at many different angles, it becomes possible to determine the degree to which each tiny block of tissue blocked the beam. For example, bone blocks most of the X-rays, while the lungs block very little. Through a complex series of computations, it’s possible to reconstruct the measurements into two-dimensional images of a patient’s internal anatomy. </p>
<p>Thanks to Fourier and <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2963745/">today’s powerful computers</a>, doctors can create almost instantaneous images of the brain, the pulmonary arteries, the appendix and other parts of the body. This in turn makes it possible to confirm or rule out the presence of issues such as blood clots in the pulmonary arteries or inflammation of the appendix. It’s difficult to imagine practicing medicine today without such CT images.</p>
<h2>Greenhouse effect</h2>
<p>Fourier is generally regarded as the <a href="https://history.aip.org/climate/co2.htm">first scientist</a> to notice what we today call the greenhouse effect. </p>
<p>His interest was piqued when he observed that a planet as far away from the sun as Earth should be considerably cooler. He hypothesized that something about the Earth – in particular, its atmosphere – must enable it to trap solar radiation that would otherwise simply radiate back out into space.</p>
<p>Fourier <a href="http://www.phys.ufl.edu/%7Ebernard/met1010_S05/warming.pdf">created a model</a> of the Earth involving a box with a glass cover. Over time, the temperature in the box rose above that of the surrounding air, suggesting that the glass continually trapped heat. Because his model resembled a greenhouse in some respects, this phenomenon came to be called the “greenhouse effect.” </p>
<p>Later, scientist John Tyndall <a href="http://www.rigb.org/our-history/iconic-objects/iconic-objects-list/tyndall-radiant-heat">discovered</a> that carbon dioxide can play the role of heat trapper.</p>
<p>Life on earth as we know it would not be possible without the greenhouse effect. However, today scientists tend to be more concerned about <a href="http://whrc.org/publications-data/understanding-climate-change-a-primer/">an excess of greenhouse gases</a>. Mathematical models suggest that as carbon dioxide accumulates, heat may be trapped more quickly, resulting in elevated global average temperatures, melting polar ice caps and rising sea levels.</p>
<h2>Fourier’s impact</h2>
<p>Fourier received many <a href="https://www.aps.org/publications/apsnews/201003/physicshistory.cfm">honors</a> during his lifetime, including election to the French Academy of Science.</p>
<p>Some believed, perhaps speciously, that Fourier’s attraction to heat may have hastened his death. <a href="http://lpsa.swarthmore.edu/Fourier/Series/FourierBio.html">He was known</a> to climb into saunas in multiple layers of clothes, and his acquaintances claimed that he kept his rooms hotter than Hades. At any rate, in May 1830, he died of an aneurysm at the age of 63. </p>
<p>Today, Fourier’s name is inscribed on the Eiffel Tower. But more importantly, it is immortalized in Fourier’s law and the Fourier transform, enduring emblems of his belief that mathematics holds the key to the universe.</p>
<p><em>This article has been updated to correct the year that Fourier traveled to Egypt.</em></p><img src="https://counter.theconversation.com/content/90906/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Fourier’s discoveries can still be felt in modern-day radiology, climate science and physics.Richard Gunderman, Chancellor's Professor of Medicine, Liberal Arts, and Philanthropy, Indiana UniversityDavid Gunderman, PhD student in Applied Mathematics, University of Colorado BoulderLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/788572017-06-07T15:29:41Z2017-06-07T15:29:41ZKenya has gaps in diagnosing and managing epilepsy<figure><img src="https://images.theconversation.com/files/172452/original/file-20170606-3662-14ha5g9.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Epilepsy is a chronic disorder of the brain characterised by recurrent seizures.</span> <span class="attribution"><span class="source">Shutterstock</span></span></figcaption></figure><p><em>Epilepsy affects the brain and causes repeated seizures. Prompt diagnosis and effective management are key to controlling the condition, the cause of which is not fully understood . There are huge gaps in the way that epilepsy is managed in African countries, including Kenya. The Conversation Africa’s Health Editor Joy Wanja Muraya spoke to Dr Symon Kariuki on what success might look like.</em></p>
<p><strong>Can you explain epilepsy, and its prevalence in Kenya?</strong></p>
<p>Epilepsy is a serious <a href="https://www.ncbi.nlm.nih.gov/pubmed/24730690">condition</a> affecting the nervous system. Unprovoked repetitive seizures, often leading to a loss of consciousness, are common in persons with epilepsy. Epilepsy can affect any person irrespective of age, sex, economic or geographic location.</p>
<p>The actual cause of epilepsy is not fully <a href="http://www.edmontonepilepsy.org/epilepsy/causes.html">understood</a>, and research about this is ongoing. What’s <a href="https://www.ncbi.nlm.nih.gov/pubmedhealth/PMHT0023035/">known is that</a> seizures are caused by abnormal and excessive electrical discharges in the brain.</p>
<p>Research in <a href="http://onlinelibrary.wiley.com/doi/10.1111/epi.12236/full">Kenya</a> rates birth trauma, infections of the brain and head injuries as the top causes. Other <a href="https://www.ncbi.nlm.nih.gov/pubmed/24116877">risk factors</a> include a family history of seizures.</p>
<p>The severity of symptoms depends on which part of the brain is affected. The seizures can present as visible fits or convulsions, muscle contractions, odd stares, impaired awareness or confusion and behaviour like lip smacking, cycling movements, or moaning.</p>
<p>According to a <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4114531/">study</a> we conducted in rural Kenya and other African countries, half of the 2,170 people with active convulsive epilepsy were children and 69% of the seizures began in childhood.</p>
<p>Other studies found that the prevalence of epilepsy is about 20 cases in every 1,000 people. About 77 new cases in every 100, 000 people are diagnosed every year. These estimates are <a href="http://www.who.int/mediacentre/factsheets/fs999/en/">two to three</a> times higher than in developed countries.</p>
<p><strong>What about diagnosis and treatment of the disease in Kenya?</strong></p>
<p>A detailed medical history from the patient, family members and eyewitnesses is an important diagnosis step in patients with repeated unprovoked seizures. The health worker takes a history of the seizures, the triggers and the date they began. Recorded videos of seizures should be also considered. </p>
<p>Laboratory blood tests are done to rule out severe seizures. One seizure doesn’t signify an epilepsy diagnosis because up to <a href="http://www.who.int/mediacentre/factsheets/fs999/en/">10% </a> of people globally can have a seizure during their lifetime. Epilepsy is defined as having two or more unprovoked seizures.</p>
<p>The measurement of electrical activity in different parts of the brain through a test known as an <a href="http://www.hopkinsmedicine.org/healthlibrary/test_procedures/neurological/electroencephalogram_eeg_92,P07655/">electroencephalography</a> can diagnose some forms of epilepsy particularly in people without physical signs of the condition.</p>
<p>Imaging tests like computed tomography (CT) scan and Magnetic resonance imaging (MRI) can be prohibitive because they are expensive and thus unavailable in many rural areas in Kenya. But people with a history of birth problems or head injuries should take them.</p>
<p>Epilepsy treatment drugs should be given immediately on diagnosis to control seizures and improve the quality of life. An epilepsy specialist may also prescribe a specific class of drugs for prolonged seizures.</p>
<p><strong>Where are the gaps in Kenya?</strong></p>
<p>Kenya’s lack of accessible and affordable health care is a <a href="https://www.ncbi.nlm.nih.gov/pubmed/22770914">major gap</a>. There’s also a lack of awareness about the disease. </p>
<p>About <a href="http://www.kawe-kenya.org/wp-content/uploads/2016/03/Epilepsy-Guidelines-2016.pdf">70%</a> of newly diagnosed children and adults with epilepsy can be successfully treated with anti-epileptic drugs. But in Kenya the diagnosis rate is still very poor.</p>
<p>Often medical treatment isn’t sought because some people believe that epilepsy is caused by a person being possessed by supernatural forces or powers. This increases stigma and discrimination. </p>
<p>Some persons with epilepsy express concerns about the negative effects of the available epilepsy drugs, which can discourage medical treatment. This can be addressed by the government investing in newer tolerable drugs.</p>
<p>Kenya has a few epilepsy specialists, about <a href="http://pn.bmj.com/content/6/4/261">25 </a>including neurologists, neurosurgeons and epileptologists- experts in epileptic seizures and seizure disorders. However they’re mostly based in cities. On top of this there aren’t services, like neurosurgeons and imaging facilities, in rural and semi-urban areas.</p>
<p>Kenya can learn from countries like <a href="https://worldneurologyonline.com/article/pediatric-neurology-in-africa/">South Africa</a> which is leading in training epilepsy specialists. <a href="https://www.ncbi.nlm.nih.gov/pubmed/10771243">Zimbabwe </a> and The Gambia are working to incorporate managing epilepsy into primary health care provision.</p>
<p><strong>What is the way forward?</strong></p>
<p>Narrowing the treatment gap in Kenya should be a collaborative effort between the ministry of health, stakeholders of epilepsy care, and research institutions.</p>
<p>As a first step training more health workers would <a href="http://www.nation.co.ke/news/Improve-health-systems-to-manage-epilepsy/-/1056/3214106/-/g8afcj/-/index.html">strengthen</a> primary health care. This would ensure that epilepsy is identified early enough to begin treatment.</p>
<p>Public health education would improve knowledge of the disease and reduce stigma and discrimination. Support groups and community epilepsy clinics could also be supported to increase epilepsy awareness. <a href="https://www.ncbi.nlm.nih.gov/pubmed/24447063">Sustained </a> health education improves knowledge about epilepsy.</p>
<p>Research institutions are critical in setting up epidemiological studies to provide reliable epilepsy data. This would make planning care much easier.</p>
<p>And evaluating the effectiveness of available or new epilepsy drugs is critical. In addition, ongoing research has the potential to quantify the burden of epilepsy in urban areas, and possibly preventable risk factors.</p><img src="https://counter.theconversation.com/content/78857/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Symon Kariuki received funding from Wellcome trust between 2012-2016 to support his PhD studies. </span></em></p>Epilepsy affects around 70 million people globally, 80% live in developing countries. A shortage of specialists, equipment and drugs complicates effective treatment and management.Symon Kariuki, Postdoctoral research student, KEMRI-Wellcome Trust Research Programme, Kenya Medical Research InstituteLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/722862017-02-13T11:24:06Z2017-02-13T11:24:06ZTechnology has confirmed a theory about Earth’s oldest venomous species<figure><img src="https://images.theconversation.com/files/155153/original/image-20170201-12651-1s12ati.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A reconstruction of Euchambersia with its venomous and ridged fangs. </span> <span class="attribution"><span class="source">SimplexPaléo/Alex Bernardini (alex-bernardini.fr)</span></span></figcaption></figure><p>Baron Franz Nopcsa is a particularly colourful figure in the history of palaeontology. He was an Austro-Hungarian aristocrat who <a href="http://www.smithsonianmag.com/history/history-forgot-rogue-aristocrat-discovered-dinosaurs-died-penniless-180959504/">discovered and identified</a> a number of dinosaurs and other fossils around the world. In 1933, during a trip to South Africa, he looked at the remains of a therapsid found a couple of years earlier by Robert Broom, a pre-mammalian relative called <a href="http://www.prehistoric-wildlife.com/species/e/euchambersia.html">Euchambersia</a>. </p>
<p>Nopcsa declared that this was probably the earliest venomous species ever recorded. But his theory couldn’t be confirmed or disproved because venom and venom glands don’t fossilise. That’s where technology comes in. I was part of a team at Johannesburg’s University of the Witwatersrand that collaborated with London’s Natural History Museum to <a href="http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0172047">test</a> Nopcsa’s theory using CT scanning and 3D imaging techniques.</p>
<p>The <a href="http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0172047">results</a>? Nopcsa was right, and at 255 million years old, Euchambersia is officially the oldest venomous animal that ever roamed the Earth.</p>
<p>Even more intriguing is that Euchambersia is related to early mammals, not to snakes (which is probably the creature you think of when it comes to venom). Actually, many existing mammals produce venom: among them shrews, some primates and the weird Australian Platypus. Numerous scientists have <a href="https://www.app.pan.pl/article/item/app51-001.html">hypothesised</a> that mammals were all venomous in the distant past but lost their venom producing glands along the way.</p>
<p>So how did we discover the truth about Euchambersia?</p>
<h2>Uncovering Euchambersia’s secrets</h2>
<p>Broom’s find is one of only two Euchambersia specimens ever discovered. Both were discovered in the same area, near the town of Colesberg in South Africa. One is kept at the <a href="http://www.nhm.ac.uk/">Natural History Museum</a> in London; the other at the <a href="https://www.wits.ac.za/esi/">Evolutionary Studies Institute</a> in Johannesburg. </p>
<p>Each specimen was CT scanned at its respective institute, and the London data was sent to my colleagues and I in Johannesburg. CT scanning is a cutting edge technique that resembles medical imaging. It allows scientists to observe and “dissect” fossils digitally using computer software. Thanks to this technique, we can produce 3D models of previously unreachable internal structures. </p>
<p>With these virtual images of the internal anatomy of the only two known specimens of Euchambersia, we had in hand the most comprehensive dataset about this species that’s ever been gathered. </p>
<p>Analysing them, we made several fascinating discoveries. It emerged that Euchambersia had anatomical adaptations which were compatible with venom production.</p>
<p>First, there was a wide, deep and circular depression in the skull for a venom gland on the upper jaw. This was connected to the canine teeth and the mouth by a fine network of bony tubes and furrows. We also discovered previously undescribed teeth hidden in the vicinity of the bones and sediment that filled the skull. As is usual for fossils, the skull is filled with sediment and some teeth were preserved inside this sediment but hadn’t been spotted before. These were two incisors with preserved crowns and a pair of large canines, all ornamented with a sharp ridge. </p>
<p>A ridged dentition like this would have helped Euchambersia to inject venom into its prey. Pre-mammalian therapsids dominated terrestrial ecosystems well before dinosaurs even appeared. They diversified as herbivores and carnivores, large and small, burrowing and ground-dwelling species. As the earliest venomous species and a representative of this early wave of pioneering species, Euchambersia directly reflects the extraordinary adaptive capabilities of these mammalian forerunners. </p>
<p>In addition, since mammals might have been primitively venomous, Euchambersia would be one of the last remnant of this distant and toxic ancestry of ours.</p><img src="https://counter.theconversation.com/content/72286/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Julien Benoit receives funding from PAST and its Scatterlings projects; the National Research Foundation of South Africa; and the DST-NRF Centre of Excellence in Palaeosciences (CoE in Palaeosciences). </span></em></p>CT scanning allows scientists to observe and “dissect” fossils digitally using computer software - and to uncover secrets that are hundreds of millions of years old.Julien Benoit, Postdoc in Vertebrate Palaeontology, University of the WitwatersrandLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/614232016-07-20T20:04:34Z2016-07-20T20:04:34ZA new brain-warp technique that helps to reconstruct fossil brains<figure><img src="https://images.theconversation.com/files/131035/original/image-20160719-13851-12890q7.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The Australian lungfish has a bigger brain than you might think.</span> <span class="attribution"><span class="source">Alice Clement</span>, <span class="license">Author provided</span></span></figcaption></figure><p>Fish have relatively small brains, especially in comparison to birds and mammals. But the picture of how brains evolved, as restored from the spaces inside fossil skulls, might not be as simple as once thought. </p>
<p>There are some groups of fish, such as some sharks and rays, that actually have a very large brain size relative to their body mass. <a href="http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0141277">Recent work</a> shows that a group of fish called <a href="http://blog.fishesofaustralia.net.au/?p=245">lungfish</a> also have relatively large brains, one that fills more than 80% of the cranial cavity.</p>
<p>This is in great contrast to their close relative the <a href="http://www.wired.com/2015/03/creature-feature-10-fun-facts-coelacanth/">coelacanth</a> whose brain fills a very small percentage of its cranial cavity (thought to be only 1%). </p>
<p>Lungfish have long fascinated researchers due to their close relationship with the <a href="http://evolution.berkeley.edu/evolibrary/article/evograms_04">tetrapods</a> – the land-dwelling animals with a backbone, which includes ourselves. </p>
<p>Lungfish can be thought of as our fishy cousins, who can provide great insight into the anatomical changes in our ancient ancestors as they first crawled out of water onto land, some 370 million years ago. But how much did their brains evolve in the process?</p>
<h2>The hunt for fossil brains</h2>
<p>After an animal has died, soft tissue such as muscle breaks down quickly and doesn’t get a chance to fossilise. Because of this, palaeontologists are usually only left with the hard skeletal remains, and almost never get to see organs, such as the heart or brain. </p>
<p>But there are some remarkable exceptions; such as a recently discovered <a href="https://theconversation.com/the-first-fossilised-heart-ever-found-in-a-prehistoric-animal-57204">120 million-year-old fossilised heart</a>. Hearts are made of muscle that can be more easily fossilised compared to brains, which are made of much softer material, and so very rarely ever fossilise. </p>
<p>In 2009, Alan Pradel, from France’s Muséum National d'Histoire Naturelle, in Paris, and his team made an exceptional discovery: a <a href="http://www.pnas.org/content/106/13/5224.full">fossilised brain</a> preserved in a 300 million-year-old cartilaginous fish. Like the coelacanth, this fish had a very small brain, housed within a much larger skull cavity. </p>
<p>As actual fossilised brains are so frightfully rare, palaeontologists must instead look at the cranial endocast, a mould of the internal cavity that once housed the brain, to reconstruct brain shape. </p>
<p>To do this, you need some very well-preserved (uncrushed) fossils such as those coming from the world famous <a href="https://museumvictoria.com.au/learning-federation/video-temp/mother-fish/gogo-fish-fossils/">Gogo Formation</a> in the Kimberley region of Western Australia.</p>
<p>The fossils from Gogo are truly exceptional. The site is world renowned because 385 million-year-old fish fossils can be prepared out of limestone to yield beautifully preserved three-dimensional skulls. They look like they died only yesterday.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/130002/original/image-20160711-9302-12kalua.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/130002/original/image-20160711-9302-12kalua.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/130002/original/image-20160711-9302-12kalua.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=540&fit=crop&dpr=1 600w, https://images.theconversation.com/files/130002/original/image-20160711-9302-12kalua.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=540&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/130002/original/image-20160711-9302-12kalua.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=540&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/130002/original/image-20160711-9302-12kalua.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=678&fit=crop&dpr=1 754w, https://images.theconversation.com/files/130002/original/image-20160711-9302-12kalua.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=678&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/130002/original/image-20160711-9302-12kalua.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=678&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">A skull of one of the exceptionally preserved 3D fossils from the Gogo Formation shown in two views (<em>Rhinodipterus</em>).</span>
<span class="attribution"><span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Until recently, only a few endocasts were known. These were fossils that had been split in half with hammers or serially ground away to reveal glimpses of the internal anatomy. Although this method can reveal amazing results, it requires destroying rare and irreplaceable specimens. </p>
<p>Palaeontologists have recently found a way around this dilemma. We now routinely scan our specimens using <a href="http://www.insideradiology.com.au/pages/view.php?T_id=61">CT scan machines</a>, like those used in hospitals, to reveal internal features without destroying the specimen. This enables us to see inside fossil skulls and start piecing together the evolutionary history of the vertebrate brain. </p>
<p>The first fossil lungfish to receive this treatment was one of those spectacular Gogo fossils called <a href="http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0113898"><em>Rhinodipterus</em></a> – named Rhino for its long nose. </p>
<h2>Doing the brain-warp</h2>
<p>Our team identified 12 points (distinct regions) on both skulls to make direct comparison between the endocasts of the living Australian lungfish <em>Neoceratodus</em> and our fossil <em>Rhinodipterus</em>. The results are <a href="http://rsos.royalsocietypublishing.org/content/3/7/160307">published this week</a> in the Royal Society Open Science journal.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/130000/original/image-20160711-9264-h5dsyz.png?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/130000/original/image-20160711-9264-h5dsyz.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/130000/original/image-20160711-9264-h5dsyz.png?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=394&fit=crop&dpr=1 600w, https://images.theconversation.com/files/130000/original/image-20160711-9264-h5dsyz.png?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=394&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/130000/original/image-20160711-9264-h5dsyz.png?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=394&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/130000/original/image-20160711-9264-h5dsyz.png?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=495&fit=crop&dpr=1 754w, https://images.theconversation.com/files/130000/original/image-20160711-9264-h5dsyz.png?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=495&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/130000/original/image-20160711-9264-h5dsyz.png?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=495&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Reconstructing a fossil brain. Take the brain of the living lungfish and brain-warp it to fit inside a fossil endocast.</span>
<span class="attribution"><span class="license">Author provided</span></span>
</figcaption>
</figure>
<p>Using custom software, we warped the modern lungfish brain and squeezed it to fit inside the fossil lungfish endocast. In the process, we maintained the same spatial relationship between the brain and endocast in the living lungfish, and then applied this 3D data to the fossil.</p>
<p>This means, for example, that the <a href="https://www.britannica.com/science/forebrain">forebrain</a>, which has a very close fit to the cranial cavity in the living Australian lungfish was reconstructed with the same closeness of fit inside the fossil endocast.</p>
<p>Similarly, the <a href="https://www.britannica.com/science/midbrain">midbrain</a> has a looser fit compared to the forebrain, and is also reconstructed with only a loose fit inside the prehistoric lungfish. </p>
<p>Thus, for the first time ever, the brain of an ancient animal has been quantitatively reconstructed using algorithms that take all the data from the living representative (and its brain shape) to create a fossil reconstruction. </p>
<p>We believe our new brain-warp technique can be adopted across many other fossil groups and will revolutionise the way scientists restore fossil brains and how they study them.</p>
<p>Our approach is much more rigorous than what has gone before. It means scientists can now draw greater inferences from endocast material and study many changes in brain evolution within fossil lineages.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/131175/original/image-20160720-8011-1iamqrg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/131175/original/image-20160720-8011-1iamqrg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/131175/original/image-20160720-8011-1iamqrg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=399&fit=crop&dpr=1 600w, https://images.theconversation.com/files/131175/original/image-20160720-8011-1iamqrg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=399&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/131175/original/image-20160720-8011-1iamqrg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=399&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/131175/original/image-20160720-8011-1iamqrg.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=502&fit=crop&dpr=1 754w, https://images.theconversation.com/files/131175/original/image-20160720-8011-1iamqrg.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=502&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/131175/original/image-20160720-8011-1iamqrg.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=502&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Brain evolution in early fishes leading up to tetrapods (right), reconstructed mostly from fossils by Lu Jing et al (2016). Lungfish are here shown by <em>Chirodipterus</em> from the Gogo site.</span>
<span class="attribution"><span class="source">Dr Lu Jing, IVPP.</span></span>
</figcaption>
</figure>
<p>In evolution, it is vital to understand how the brain has changed through time. Brains are the powerhouses that control everything from your heartbeat and breathing, to learning and emotional intelligence.</p>
<p>It is our hope that our new technique for reconstructing fossil brains will be utilised by other workers to shed more light on the early evolution of the vertebrate brain. </p>
<p>Understanding changes in the early evolution of the brain can help us understand when certain senses such as smell or vision became more important than others, and how the development of higher cognitive centres may have helped some animals flourish while others floundered.</p><img src="https://counter.theconversation.com/content/61423/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Alice Clement's position at Flinders University is funded by The Australian Research Council (grant awarded to JAL et al.)</span></em></p><p class="fine-print"><em><span>John Long receives funding from The Australian Research Council.</span></em></p>To understand how some creatures evolved, you need to see how their brain developed over millions of years. That’s now possible thanks to some clever use of scanning technology.Alice Clement, Research Associate in the School of Biological Sciences, Flinders UniversityJohn Long, Strategic Professor in Palaeontology, Flinders UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/608222016-06-24T12:40:18Z2016-06-24T12:40:18ZDo CT scans really cause cancer?<figure><img src="https://images.theconversation.com/files/127361/original/image-20160620-8885-1t1b6em.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="http://www.shutterstock.com/cat.mhtml?lang=en&language=en&ref_site=photo&search_source=search_form&version=llv1&anyorall=all&safesearch=1&use_local_boost=1&autocomplete_id=&searchterm=CT%20scan&show_color_wheel=1&orient=&commercial_ok=&media_type=images&search_cat=&searchtermx=&photographer_name=&people_gender=&people_age=&people_ethnicity=&people_number=&color=&page=1&inline=149926556">bikeriderlondon/Shutterstock.com</a></span></figcaption></figure><p>Computerised tomography (CT) scans are being increasingly used for medical diagnoses. In the UK, about <a href="http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.584.8974">3m CT scans</a> are carried out each year, and the rate per person is around <a href="http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.584.8974">five times higher</a> in the US. However, concerns have been raised about the increased risk of cancer in people who have undergone these scans.</p>
<p>A CT scan (or “CAT scan”) provides doctors with a much clearer picture of what is happening inside the body than conventional X-rays. But they also deliver a much higher dose of <a href="http://www.who.int/ionizing_radiation/about/what_is_ir/en/">ionising radiation</a>. Ionising radiation causes tissue damage and can increase the risk of cancer. The increase in risk is proportional to the amount of radiation received. </p>
<p>Risk accumulates with repeated exposure, and children are more susceptible than adults. Because CT scans require many images to be taken in the same body area, they deliver more radiation than a conventional X-ray. For example, 50 times more radiation in the abdominal area has <a href="http://bit.ly/28MHOSK">been detected</a>. But a 50-fold increase in a very small number is still a small number. </p>
<p>It has been estimated that an abdominal scan delivers about six times as much ionising radiation as a person would receive from the environment in a year. </p>
<h2>Finding a link</h2>
<p>Authors of a large UK study found that children exposed to higher radiation doses from CT scans faced threefold increases in their risks of developing leukaemia and brain tumours compared with those who received <a href="http://bit.ly/28NC7p2">lower doses</a>. The higher the amount of radiation the children received, the greater their chances of developing these cancers were. </p>
<p>The number of children diagnosed with either cancer over a 17-year period was about 200 out of 180,000 who were scanned. About 170 of these 200 children would, according to the researchers, have developed cancer as a result of having had higher radiation exposure from CT scans. (They were chosen because the authors considered them to be most affected by radiation exposure.) The overall estimated risk was therefore 170 in 180,000, or about one in a thousand. </p>
<p>But there are methodological problems with this and similar research. Some 30,000 children could not be included in the data analysis, mainly because their medical records were incomplete, and their omission might have affected the findings. And, although the researchers attempted to do so, we cannot rule out “reverse causation”, that is, some children having had more CT scans because they had underlying health problems, rather than vice versa. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/127774/original/image-20160622-7196-1tclfpv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/127774/original/image-20160622-7196-1tclfpv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=413&fit=crop&dpr=1 600w, https://images.theconversation.com/files/127774/original/image-20160622-7196-1tclfpv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=413&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/127774/original/image-20160622-7196-1tclfpv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=413&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/127774/original/image-20160622-7196-1tclfpv.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=519&fit=crop&dpr=1 754w, https://images.theconversation.com/files/127774/original/image-20160622-7196-1tclfpv.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=519&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/127774/original/image-20160622-7196-1tclfpv.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=519&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Brain cancer cells.</span>
<span class="attribution"><a class="source" href="http://www.shutterstock.com/cat.mhtml?lang=en&language=en&ref_site=photo&search_source=search_form&version=llv1&anyorall=all&safesearch=1&use_local_boost=1&autocomplete_id=&search_tracking_id=trFVqyNMqmhDf4EvaLF6sw&searchterm=brain%20cancer&show_color_wheel=1&orient=&commercial_ok=&media_type=images&search_cat=&searchtermx=&photographer_name=&people_gender=&people_age=&people_ethnicity=&people_number=&color=&page=1&inline=389772325">royaltystockphoto.com/Shutterstock.com</a></span>
</figcaption>
</figure>
<p>The researchers excluded children who were given CT scans because cancer was suspected.</p>
<p>As the authors acknowledge, this approach has limitations. Children who receive CT scans may differ from those who do not in unknown ways which also make the former more likely to develop cancer. The only way to definitively exclude reverse causation would be to do a randomised controlled trial. This would involve randomising children into higher and lower exposure groups and following them up over a long period to see how many in each group developed cancer. This would, of course, be totally unethical.</p>
<p>Also, the findings don’t exclude the possibility that children who have CT scans become at greater risk of experiencing other diseases, or over longer time periods than were considered in the study. Reverse causation might result in the risk from scans being overstated because the children who had more scans might have been more likely to develop cancers even if they had not been exposed to extra radiation. On the other hand, exclusion of other conditions and longer time periods might lead to the risk from scans being understated. Overall, there is considerable uncertainty about the risk estimates generated by the study.</p>
<h2>US study</h2>
<p>Using UK data similar to that outlined above, <a href="http://archinte.jamanetwork.com/article.aspx?articleid=415368">researchers in the US</a> concluded that about 2% of US cancers would be caused by radiation from CT scans. This conclusion is subject to the same cautions as detailed above. Also, the absence in the US of centralised databases of health records adds further complications to risk estimates. </p>
<p>If the estimate is approximately right, and current UK usage of CT scans in the UK is about a fifth of the US level, then about 0.4% of UK cancers would be caused by exposure to CT scans. Although readers may view this risk as acceptably low, it would mean that about 1,400 of the 350,000 annual <a href="http://www.cancerresearchuk.org/health-professional/cancer-statistics/incidence#heading-Zero">new cancer cases</a> estimated to occur in the UK would result from CT scans. Given the trend towards increasing medical usage, this rate can be expected to increase in the future. </p>
<h2>Comparing apples with oranges</h2>
<p><a href="http://pubs.rsna.org/doi/full/10.1148/radiol.12121248">Most experts believe</a> that the risks associated with CT scans are greatly outweighed by their benefits. This conclusion might seem worryingly tentative. However, most decisions about risks entail value judgements because like is not being compared with like, in this case the clinical benefits of having CT scans to the additional cancer risk faced by those who undergo them, including otherwise healthy people. </p>
<p>Patients and parents offered a CT scan should ask their doctor to explain why it’s needed, and whether alternatives not involving exposure to radiation could be used.</p><img src="https://counter.theconversation.com/content/60822/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Bob Heyman does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>CT scans deliver a hefty dose of ionising radiation. But the benefits outweigh the risks – most of the time.Bob Heyman, Chair professor, University of HuddersfieldLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/574062016-05-31T01:04:47Z2016-05-31T01:04:47ZHow computing power can help us look deep within our bodies, and even the Earth<figure><img src="https://images.theconversation.com/files/122911/original/image-20160517-9476-w78fh8.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The computer does more of the work than you might think.</span> <span class="attribution"><a class="source" href="http://www.shutterstock.com/pic-401715220/stock-photo-thessaloniki-greece-february-official-opening-of-the-first-ct-imaging-pet-ct-scanner.html?src=wcSemSkkJRQbjbDYm9SbKA-2-59">CT computer and scan room image via shutterstock.com</a></span></figcaption></figure><p>CAT scans, MRI, ultrasound. We are all pretty used to having machines – and doctors – peering into our bodies for a whole range of reasons. This equipment can help diagnose diseases, pinpoint injuries, or give expectant parents the first glimpse of their child.</p>
<p>As computational power has exploded in the past half-century, it has enabled a parallel expansion in the capabilities of these computer-aided imaging systems. What used to be pictures of two-dimensional “slices” have been assembled into high-resolution three-dimensional reconstructions. Stationary pictures of yesteryear are today’s real-time video of a beating heart. The advances have been truly revolutionary.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/EN5qgpVxrcU?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">A cardiac MRI scan shows a heart beating.</span></figcaption>
</figure>
<p>Though different in their details, X-ray computed tomography, ultrasound and even MRI have a lot in common. The images produced by each of these systems derive from an elegant interplay of sensors, physics and computation. They do not operate like a digital camera, where the data captured by the sensor are basically identical to the image produced. Rather, a lot of processing must be applied to the the raw data collected by a CAT scanner, MRI machine or ultrasound system to produce before it the images needed for a doctor to make a diagnosis. Sophisticated algorithms based on the underlying physics of the sensing process are required to put Humpty Dumpty back together again.</p>
<h2>Early scanning methods</h2>
<figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/122907/original/image-20160517-9491-18otosr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/122907/original/image-20160517-9491-18otosr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=360&fit=crop&dpr=1 600w, https://images.theconversation.com/files/122907/original/image-20160517-9491-18otosr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=360&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/122907/original/image-20160517-9491-18otosr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=360&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/122907/original/image-20160517-9491-18otosr.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=453&fit=crop&dpr=1 754w, https://images.theconversation.com/files/122907/original/image-20160517-9491-18otosr.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=453&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/122907/original/image-20160517-9491-18otosr.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=453&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">One of the first published X-rays (at right, with normal view of the hand at left), from 1896.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File%3AX-ray_1896_nouvelle_iconographie_de_salpetriere.jpg">Albert Londe</a></span>
</figcaption>
</figure>
<figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/122908/original/image-20160517-9464-1m98rqs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/122908/original/image-20160517-9464-1m98rqs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=367&fit=crop&dpr=1 600w, https://images.theconversation.com/files/122908/original/image-20160517-9464-1m98rqs.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=367&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/122908/original/image-20160517-9464-1m98rqs.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=367&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/122908/original/image-20160517-9464-1m98rqs.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=461&fit=crop&dpr=1 754w, https://images.theconversation.com/files/122908/original/image-20160517-9464-1m98rqs.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=461&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/122908/original/image-20160517-9464-1m98rqs.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=461&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">A modern hand X-ray.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/golanlevin/19300737031/">golanlevin/flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<p>Though we use X-rays in some cutting-edge imaging techniques, X-ray imaging actually <a href="https://www.nde-ed.org/EducationResources/CommunityCollege/Radiography/Introduction/history.htm">dates back to the late 1800s</a>. The shadowlike contrast in X-ray images, or projections, shows the density of the material between the X-ray source and the data sensor. (In the past this was a piece of X-ray film, but today is usually a digital detector.) Dense objects, such as bones, absorb and scatter many more X-ray photons than skin, muscle or other soft tissue, which appear darker in the projections.</p>
<p>But then in the early 1970s, X-ray CAT (which stands for Computerized Axial Tomography) scans were developed. Rather than taking just a single X-ray image from one angle, a CAT system rotates the X-ray sources and detectors to collect many images from different angles – a process known as tomography. </p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/yTDgFW2UZFI?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Computerized tomography imagery of a hand.</span></figcaption>
</figure>
<p>The difficulty is how to take all the data, from all those X-rays from so many different angles, and get a computer to properly assemble them into 3D images of, say, a person’s hand, as in the video above. That problem had a mathematical solution that had been studied by the <a href="https://thatsmaths.com/2013/03/07/ct-scans-and-the-radon-transform/">Austrian mathematician Johann Radon</a> in 1917 and rediscovered by the American physicist (and Tufts professor) <a href="http://www.nytimes.com/1998/05/09/us/allan-cormack-74-nobelist-who-helped-invent-cat-scan.html">Allan Cormack</a> in the 1960s. Using Cormack’s work, <a href="http://dx.doi.org/10.1148/radiol.2343042584">Godfrey Hounsfield</a>, an English electrical engineer, was the first to demonstrate a working CAT scanner in 1971. For their work on CAT, Cormack and Hounsfield received the <a href="http://www.nobelprize.org/nobel_prizes/medicine/laureates/1979/">1979 Nobel Prize in Medicine</a>. </p>
<h2>Extending the role of computers</h2>
<p>Until quite recently, these processing methods had more or less been constant since the 1970s and 1980s. Today, additional medical needs – and more powerful computers – are driving big changes. There is increased interest in CT systems that <a href="http://www.fda.gov/Radiation-EmittingProducts/RadiationEmittingProductsandProcedures/MedicalImaging/MedicalX-Rays/ucm115329.htm">minimize X-ray exposure</a>, yielding high-quality images from fewer images. In addition, certain uses, such as breast imaging, encounter physical constraints on how much access the imager can have to the body part. This requires scanning from only a very limited set of angles around the subject. These situations have led to research into <a href="http://www.massgeneral.org/imaging/services/3D_mammography_tomosynthesis.aspx">what are called “tomosynthesis” systems</a> – in which limited data are interpreted by computers to form fuller images. </p>
<p>Similar problems arise, for example, in the context of imaging the ground to see what objects – such as pollutants, land mines or oil deposits – are hidden beneath our feet. In many cases, all we can do is <a href="http://physicsworld.com/cws/article/news/2016/feb/16/ground-penetrating-radar-boosts-asparagus-production">send signals from the surface</a>, or drill a few holes to take sampling measurements. <a href="https://www.ncjrs.gov/school/ch3c_5.html">Security scanning in airports</a> is constrained by cost and time, so those X-ray systems can take only a few images.</p>
<p>In these and a host of other fields, we are faced with less overall data, which means the Cormack-Hounsfield mathematics can’t work properly to form images. The effort to solve these problems has led to the rise of a new area of research, “computational sensing,” in which sensors, physics and computers are being brought together in new ways. </p>
<p>Sometimes this involves applying more computer processing power to the same data. In other cases, hardware engineers designing the equipment <a href="https://www.ecse.rpi.edu/homepages/saulnier/eit/eit.html">work closely with the mathematicians</a> figuring out how best to analyze the data provided. Together these systems can provide new capabilities that hold the promise of major changes in many research areas.</p>
<h2>New scanning capabilities</h2>
<p>One example of this potential is in bio-optics, the use of light to look deep within the human body. While visible light does not penetrate far into tissue, anyone who has shone a red laser pointer into their finger knows that red light does in fact make it through at least a couple of centimeters. Infrared light penetrates even farther into human tissue. This capability opens up entirely new ways to image the body than X-ray, MRI or ultrasound.</p>
<p>Again, it takes computing power to move from those images into a unified 3D portrayal of the body part being scanned. But the calculations are much more difficult because the way in which light interacts with tissue is far more complex than X-rays.</p>
<p>As a result we need to use a different method from that pioneered by Cormack in which X-ray data are, more or less, directly turned into images of the body’s density. Now we construct an algorithm that follows a process over and over, feeding the result from one iteration back as input of the next. </p>
<p>The process starts by having the computer guess an image of the optical properties of the body area being scanned. Then it uses a computer model to calculate what data from the scanner would yield that image. Perhaps unsurprisingly, the initial guess is generally not so good: the calculated data don’t match the actual scans. </p>
<p>When that happens, the computer goes back and refines its guess of the image, recalculates the data associated with this guess and again compares with the actual scan results. While the algorithm guarantees that the match will be better, it is still likely that there will be room for improvement. So the process continues, and the computer generates a new and more improved guess. </p>
<p>Over time, its guesses get better and better: it creates output that looks more and more like the data collected by the actual scanner. Once this match is close enough, the algorithm provides the final image as a result for examination by the doctor or other professional.</p>
<p>The new frontiers of this type of research are still being explored. In the last 15 years or so, researchers – including my Tufts colleague <a href="https://ase.tufts.edu/biomedical/research/Fantini/">Professor Sergio Fantini</a> – have explored many potential uses of infrared light, such as <a href="http://dx.doi.org/10.1007/s10549-013-2802-9">detecting breast cancer</a>, functional brain imaging and <a href="http://dx.doi.org/10.1016/j.bbapap.2013.01.025">drug discovery</a>. Combining “big data” and “big physics” requires a close collaboration among electrical and biomedical engineers as well as mathematicians and doctors. As we’re able to develop these techniques – both mathematical and technological – we’re hoping to make major advances in the coming years, improving how we all live.</p><img src="https://counter.theconversation.com/content/57406/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Eric Miller receives funding from NSF, NIH, DHS. </span></em></p>Pairing more powerful computers with increasingly sensitive scanners can yield many benefits in medicine and other fields.Eric Miller, Professor and Chair of Electrical and Computer Engineering, Adjunct Professor of Computer Science, Adjunct Professor of Biomedical Engineering, Tufts UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/561562016-03-15T04:15:51Z2016-03-15T04:15:51ZScans and DNA tests reveal the secrets of a rare African mummy<figure><img src="https://images.theconversation.com/files/114912/original/image-20160314-11302-zachht.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">A three-dimensional volume rendering of the Tuli mummy.</span> <span class="attribution"><span class="source">SA Journal of Science</span></span></figcaption></figure><p><em>He lay alone in a shallow grave at the base of a cliff for hundreds of years. Then, in 2008, patrol staff at a game lodge stumbled across the man’s remains - and he became the <a href="http://repository.up.ac.za/bitstream/handle/2263/19039/Mosothwane_Tuli%282011%29.pdf?sequence=1&isAllowed=y">first mummy</a> ever found in Botswana. Now a team of scientists from Botswana, South Africa and Switzerland has used <a href="http://www.fda.gov/Radiation-EmittingProducts/RadiationEmittingProductsandProcedures/MedicalImaging/MedicalX-Rays/ucm115318.htm">computerised tomography</a> (CT) scanning and <a href="http://www.sfu.ca/ipinch/resources/fact-sheets/ancient-dna-adna-what-it-why-it-important">ancient DNA</a> analysis to <a href="http://www.sajs.co.za/radiological-and-genetic-analysis-late-iron-age-mummy-tuli-block-botswana/frank-j-r%C3%BChli-maryna-steyn-morongwa-n-mosothwane-lena-%C3%B6hrstr%C3%B6m-molebogeng-k-bodiba-abigail-bouwman">uncover</a> some of the Tuli mummy’s secrets. The Conversation Africa’s science and technology editor Natasha Joseph asked two of the study’s authors, Maryna Steyn and Frank Rühli, to explain what they found.</em></p>
<p><strong>The Tuli mummy is one of a kind, so mummification obviously wasn’t a common practise in Botswana. Was it common elsewhere in southern Africa?</strong></p>
<p>Mummification was not common in southern Africa, but it did happen. This is the first mummy found in Botswana. A few have been found in neighbouring South Africa, like the 2000 year old <a href="http://repository.up.ac.za/bitstream/handle/2263/5758/Steyn_Kouga(2007).pdf?sequence=1">Kouga mummy</a>.</p>
<p>Ethnographic literature, particularly focusing on Zimbabwe, <a href="http://stpxml.sourceforge.net/Sites/Stilbaai/KRK/pdf/front.pdf">suggests</a> that after a leader died, his body was not immediately interred but may have been treated by
usually slowly drying it over a low fire. This may have assisted in the preservation of such a body. The body would then be wrapped in a cloth or bull hide and buried at the same time that the leader’s successor came to power. </p>
<p>The Tuli remains were not intentionally mummified - they mummified by accident. The dry conditions led to the drying out, or dessication, of the remains. This contributed to the mummification or preservation of soft tissues such as skin and tendons. So the remains were naturally mummified.</p>
<p><strong>How does one perform a CT scan on a mummy? It must be quite risky, given the fragile condition of the remains. Is it a common procedure elsewhere in the world where mummies are found more frequently?</strong></p>
<p>Modern imaging techniques have opened up a whole new world when it comes to mummy studies. CT scans are frequently used, though it can be a risky process - the mummy can be damaged during transportation and scanning. The scientists involved usually wrap the mummy and wear gloves as much as possible so that the mummy isn’t physically damaged.</p>
<figure class="align-left ">
<img alt="" src="https://images.theconversation.com/files/114913/original/image-20160314-11288-1nzzvew.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/114913/original/image-20160314-11288-1nzzvew.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=450&fit=crop&dpr=1 600w, https://images.theconversation.com/files/114913/original/image-20160314-11288-1nzzvew.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=450&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/114913/original/image-20160314-11288-1nzzvew.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=450&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/114913/original/image-20160314-11288-1nzzvew.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=566&fit=crop&dpr=1 754w, https://images.theconversation.com/files/114913/original/image-20160314-11288-1nzzvew.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=566&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/114913/original/image-20160314-11288-1nzzvew.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=566&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The intact mummy, covered with animal skin, as it was discovered at the base of a cliff in Botswana.</span>
<span class="attribution"><span class="source">SA Journal of Science</span></span>
</figcaption>
</figure>
<p>Also, as these mummies are not in the same position a living patient would be - supine, straight or on their back - it is sometimes difficult to fit them into the scanner. The Tuli mummy, for instance, was found curled up into a foetal position. These unusual body positions sometimes make it difficult to interpret the scans’ findings.</p>
<p>But CT scans give us the chance to get really important medical and archaeological information through non-invasive examinations.</p>
<p><strong>What did the CT scans and DNA analysis tell you about the Tuli mummy? Who was he?</strong></p>
<p>In the initial study his age was estimated to be between 40 and 55, but the new information from our scans suggests that the Tuli mummy was definitely older than 50. He lived during the Iron Age or, more specifically, the <a href="http://www.annualreviews.org/doi/pdf/10.1146/annurev.an.11.100182.001025">Late Iron Age</a>, and suffered from degenerative disease, especially of the spine. We could tell this because of the osteophytes along his spine. These are bony projections that suggest degeneration of the joints.</p>
<p>The scans didn’t reveal any preserved organs, which means they either degenerated after death or were removed before burial. The second is unlikely, since it would be unusual practice in the area.</p>
<p>We also did aDNA analysis, which stands for ancient DNA. It is old, and therefore difficult to extract. One has to do this in a specialised aDNA laboratory. One of the co-authors on our paper in the SA Journal of Science was Molebogeng Bodiba, who travelled to Switzerland to work in a dedicated aDNA lab.</p>
<figure>
<iframe width="440" height="260" src="https://www.youtube.com/embed/X3OF5HsfN5g?wmode=transparent&start=0" frameborder="0" allowfullscreen=""></iframe>
<figcaption><span class="caption">Extracting ancient DNA is a delicate, fascinating process.</span></figcaption>
</figure>
<p>The Tuli mummy marks the first time that ancient DNA has been extracted from a southern African mummy. Generally speaking, this helps scientists to get a better understanding of things like local population genetics.</p>
<p>His aDNA revealed that Tuli was related to modern day <a href="http://www.sahistory.org.za/people-south-africa/sotho-south-sotho-or-basotho">Sotho-Tswana</a> and <a href="https://www.sciencedaily.com/releases/2012/09/120920141139.htm">Khoesan</a> people. This is what we would have expected, but it’s great to have it confirmed and to see that the technology works.</p><img src="https://counter.theconversation.com/content/56156/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Maryna Steyn receives funding from the National Research Foundation</span></em></p><p class="fine-print"><em><span>Frank Rühli does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Modern techniques such as CT scanning and ancient DNA analysis have allowed scientists to discover a great deal about a mummy found in a shallow grave in Botswana.Maryna Steyn, Professor; Head of the School of Anatomical Sciences, University of the WitwatersrandFrank Rühli, Director of the Institute of Evolutionary Medicine, University of ZurichLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/251292014-04-02T13:42:03Z2014-04-02T13:42:03ZStartling images show strange and beautiful science up close<p>Widening our view of the world can mean taking a much closer look at the familiar. And technology from MRI to <a href="http://www.ammrf.org.au/myscope/sem/background/">Scanning Electron Microscopes</a>, which use focused beams to interact with a sample’s surface to produce nano-sized resolution, is allowing scientists and medical researchers to delve into our strange and beautiful world (sometimes aided with a little Photoshop). </p>
<p>Three academics with winning entries in this year’s <a href="http://www.wellcomeimageawards.org/">Wellcome Image Awards</a> tell us how they got their image. </p>
<hr>
<p><strong>Kevin Mackenzie, Microscopy Manager, Institute of Medical Sciences, University of Aberdeen</strong></p>
<p>I’m always on the lookout for new and interesting specimens to image and when I had kidney stones a few years ago I managed to collect one. I decided to image in the light microscope, Micro CT and also under the Scanning Electron Microscope (SEM). The resulting image was taken using a Zeiss MA10 SEM and false coloured using Adobe Photoshop. The size of the stone is 2mm across (which is quite small for a kidney stone).</p>
<p>Kidney stones form when salts, minerals and chemicals in the urine (for example calcium oxalate and uric acid) clump together and solidify. Small kidney stones are often passed naturally, but larger stones sometimes get stuck in the kidney or in the tubes that carry urine out of the body.</p>
<p>I was very happy to have another two images selected for the awards, one was a Scanning Electron Micrograph of a single head louse egg attached to a human hair, and the other was a Micro CT scan of a medieval (so over 1000 years old) jawbone.</p>
<hr>
<p><strong>Zeynep Saygin, Postdoctoral Researcher in the Department of Brain and Cognitive Sciences at MIT</strong></p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/45394/original/d5zn9q47-1396435041.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/45394/original/d5zn9q47-1396435041.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=511&fit=crop&dpr=1 600w, https://images.theconversation.com/files/45394/original/d5zn9q47-1396435041.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=511&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/45394/original/d5zn9q47-1396435041.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=511&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/45394/original/d5zn9q47-1396435041.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=642&fit=crop&dpr=1 754w, https://images.theconversation.com/files/45394/original/d5zn9q47-1396435041.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=642&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/45394/original/d5zn9q47-1396435041.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=642&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Adult brain nerve fibres.</span>
<span class="attribution"><span class="source">Zeynep M. Saygin, McGovern Institute, MIT</span></span>
</figcaption>
</figure>
<p>My image depicts the nerve fibres, or wiring, of the healthy human brain. Brain cells communicate with each other through these fibres and we can visualise them in every individual using a specialised MRI scan. The colours represent the direction of the fibres: blue for those that travel up and down; green for front to back; and red for left to right. </p>
<p>I am continually astounded by the number and complexity of these nerve fibres; what information do these connections carry and how do they orchestrate complex mental processes? My research combines these images of connectivity with neural response patterns in order to understand the complex circuitry of the brain, and how it ultimately shapes who we are.</p>
<hr>
<p><strong>Sergio Bertazzo, Junior Research Fellow, Imperial College London</strong></p>
<p>This is a density-dependent colour scanning electron micrograph of the surface of human heart (aortic valve) tissue. The spherical particles show calcification. The orange colour identifies denser material (calcified material composed of calcium phosphate), while structures that appear in green are less dense (corresponding to the organic component of the tissue). </p>
<p>The discovery of calcified particles shows that calcification in the cardiovascular system is more complex than being just a regular process of bone formation.</p>
<h2>Best of the rest</h2>
<p><strong>Anders Persson, Director of the Centre for Medical Image Science and Visualisation at Linköping University, Sweden</strong></p>
<p>The overall winner, this image was created from a new type of scan called dual energy computed tomography (DECT) angiography. Unlike CT scanning, DECT uses two sources of X-rays at different energies. These are then digitally reconstructed in 3D and can be rotated, sliced or magnified.</p>
<p><strong>Khuloud T Al-Jamal, Senior Lecturer in Nanomedicine, and Izzat Suffian, PhD, King’s College London</strong></p>
<p>Scanning Electron Micrograph of a cluster of breast cancer cells (in blue) treated with nanometre-sized particles that carry the anti-cancer drug doxorubicin. This causes some of the cells (in purple) to die through a process known as programmed cell death, where cells effectively commit suicide in a controlled, predictable way. Turning this on in cancer cells can reduce a tumour’s size.</p>
<p><strong>Annie Cavanagh and David McCarthy, Microscopists</strong></p>
<p>Scanning electron micrograph of a four-day-old zebrafish embryo. To capture this image, the zebrafish was physically attached to a stub (specimen holder) by its tail and tilted to 65 degrees. As zebrafish embryos are approximately 1cm in length, making the whole embryo too big to be captured in a single image, three separate images had to be taken along its length and then stitched together digitally. Colour was then added to the black-and-white image.</p>
<p><strong>Chris Thorn, Medical Artist</strong></p>
<p>X-ray projection of a brown long-eared bat hunted and killed by a domestic cat. The bat’s height is about 5cm.</p><img src="https://counter.theconversation.com/content/25129/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Widening our view of the world can mean taking a much closer look at the familiar. And technology from MRI to Scanning Electron Microscopes, which use focused beams to interact with a sample’s surface…Kevin Mackenzie, Microscopy and Histology Core Facility Manager, University of AberdeenSergio Bertazzo, Junior Research Fellow, Imperial College LondonZeynep Saygin, Postdoctoral Researcher, Massachusetts Institute of Technology (MIT)Licensed as Creative Commons – attribution, no derivatives.