The skeleton above was created by taking a CT scan of an anesthetized rat and sending the data to a 3-D printer. Similar life-size models of body parts from other animals or human patients could be used to train veterinary and medical students and to help surgeons prepare for difficult surgeries, the researchers say.

The idea to print skeletons from CT scans came from Evan Doney, an engineering student working in the lab of Matthew Leevy, who runs the biological imaging facility at the University of Notre Dame. "At first I didn't really know what the killer app would be, I just knew it would be really cool," Leevy said. But he began to see new possibilities after striking up a conversation with an ear, nose, and throat specialist during an office visit for a sinus problem. "I actually got out my computer and showed him some slides, and by the end of it we were collaborating."

Doney used several freeware programs to convert data from CT scans into a format that could be read by a 3-D printer. As a proof of principle, he and colleagues printed a rat skeleton in white plastic and printed a removable set of lungs in green or purple. They also printed out a rabbit skull.

They recently presented these models and a video how-to guide in the Journal of Visualized Experiments (see below).

Image: Matthew Leevy/University of Notre Dame

Similarly made 3-D models based on CT scans from individual patients could help surgeons prepare for tricky surgeries, such as removing hard-to-access tumors in or around the airway, Leevy says. "Ideally they'd have the whole head right in front of them, with all the anatomy preserved, and the tumor printed out in a different color of plastic within the model."

The models could be a boon for education too. A high-quality cast of a human skull costs hundreds of dollars, and a complete skeleton can set you back thousands, Leevy notes. 3-D printed skulls would be far cheaper. "At Notre Dame, there are 100 kids in anatomy class and they have to share 5 skulls," he said. "For 10 to 20 bucks they could each have their own skull to take back to their dorm to study."

CT scans from patients with various diseases could also be converted into models for students to study.

And that's not all, Leevy says. "We can also use our approach to print skulls in which various anatomical structures are printed in a separate color, or in glow in the dark plastic, to highlight them and further facilitate the learning process."