University of Washington biology professor Adam Summers no longer relies on CT scanners at hospitals to visualize the inner structures of stingrays and other fish.
Last fall, he installed a small computed tomography, or CT, scanner at the university’s Friday Harbor Laboratories and launched an ambitious project to scan and digitize more than 25,000 types of fish.
The idea is to have one clearinghouse of CT scan data freely available to researchers anywhere to analyze the morphology, or structure, of particular species.
So far, he and others have digitized images of more than 500 species from museum collections around the globe. He plans to add thousands more and has invited other scientists to use the CT scanner, or add their own scans to the open-access database.
“We have folks coming from all over the world to use this machine,” said Summers, who advised Pixar on how fish move for its hit animated films “Finding Nemo” and “Finding Dory” and is dubbed “fabulous fish guy” on the credits for “Nemo.”
Like hospital scanners, Summers’s device takes X-ray images from various angles and combines them to create three-dimensional images of the fish.
With each CT scan he posted to the Open Science Framework, a sharing website, people would ask him, “What are you going to scan next?” He would respond: “I want to scan them all. I want to scan all fish.”
Then he developed techniques, such as scanning multiple specimens, that put the goal within reach, he said, and suddenly a project that easily could have taken 50 years boiled down to just a few years.
“It wasn’t just a joke anymore. We could actually say it and have a hope of actually getting every fish scanned,” he said.
Scans typically cost $500 to $2,000 each, but Summers’s project provides free access to the images. Summers recalled how as a graduate student 17 years ago he bribed a technician with Snickers bars to scan large stingrays in a hospital CT scanner.
At the time, he said, he wanted to know how an animal with a skeleton composed of cartilage could do such “a crazy thing” as crush hard prey, such as snails and mussels. The medical CT scan helped offer an answer: The stingray had mineralized tissue in its cartilage.
So began his fascination with CT scans as a way to uncover other puzzles: What’s the structure of a stingray’s wing? How does one scale in an armored fish overlap with another, and what are the implications for movement?
Summers is also known for his fish photographs — stunning images that have been stained with red and blue dyes to highlight cartilage and bone — which have been shown at the Seattle Aquarium.
Malorie Hayes, a graduate student at Auburn University, took Summers up on his offer to use the scanner after hearing him talk about the project at a recent conference. Soon, she’ll fly to the lab to scan more than 200 species of African barbs, a small freshwater fish.
Such fish are rare and difficult to obtain, she said. CT scans offer a nondestructive way to study those bones. “Instead of having to cut them open, I can visualize the skeletons,” she said. “There are lots of questions that can be answered just by looking at their skeletons.”