For Radiologist and designer Ethan Broadaway, it all began with 3D printing a "very small Darth Vader figure" for his son. That tiny, domestic first step led to some pioneering work developing a printed bone graft substitute in conjunction with Amit Govil, the President and founder of Advanced Biologics.

The project was aimed at visualizing the progress and impact of translating patient data in the form of CT scans to create physical models for use in Biomedical Engineering.

The bone graft substitutes are generated via a patented process using tissue from donors. They rely on cutting edge medical imaging technology the developers use to understand how and why the practice of medicine could benefit from translating that data from the digital realm into the physical realm, via modern 3D printing techniques.

According to Broadaway, the bone graft project was a natural evolution of his 3D work in the various clinical settings. The 38 year-old Broadaway earned a degree from Arkansas State University Jonesboro in Radiologic Science and Imaging Physics, and working from an office overlooking the Mission Valley area outside of San Diego, CA, he used an Afinia printer for his work.

Broadaway was tasked with arriving at a solution designed to show potential clients how the product performed after surgery, and while he'd dabbled in 3D printing for a few years, it was a chance meeting with Mitch Ackman and Aaron Pratt of Afinia which moved the project forward.

"Meeting Mitch and Aaron was really a stroke of luck," Broadaway said. The Afinia 3D printer looked like it could do the job and was reasonably priced, so I bought one."

He then began to work on translating surgical process CT scan data into printed 3D models.

"The major issue we had with translation from CT data to a 3D printable model was not the actual print so much as the difficulty in cleaning and separating the unwanted raft material from the finished print," Broadaway said. "The fidelity of the CT scan allows for extensive detail in the conversion process, to keep from chipping away at that detail when removing the raft material takes a steady, patient hand."

A model with support material intact The same model after cleanup

According to Broadaway, readying CT scan data for 3D printing depends largely on the scan density ordered by the orthopedist, and he found that only a small percentage of all scans had the correct data density required for a good 3D print. He then set to work developing his methodology. He imports the CT scan into modeling software, makes edits and then exports a finished STL file, which is sent to his Afinia 3D printer.

"The first couple of tries were a bit rough, but once I got the hang of it, I was able to produce some really useful models," Broadaway said. "We had a trade show coming up and I needed to produce a large number of models. I had my first Afinia printer maxed out, so I bought another one to keep up with the demand. The models were very well received by potential clients which allowed us to gain much greater acceptance of our client's product."

Primary modeling for the bone graft substitutes is accomplished within Luxology/The Foundry's MODO 701 and the source materials are taken from a DICOM-compatible PACS system, Osirix. Osirix includes a variety of plug-ins and features he uses as a starting point for compiling the data into a 3D printer-friendly format.

"It's just getting started. We've seen this technology used to fabricate one-off individualized tools, produce models we would be unable to assemble in the real world and to extend the life of some items that would work their way into a landfill otherwise by printing replacement parts," Broadaway said. "Only when you consider how powerful it can be to quickly bring a digital object into the physical world does the hidden potential of 3D printing emerge."