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Practice Makes Perfect

Kip Hanson
By Kip Hanson Contributing Editor, SME Media

Sarah Rimini wears a lot of hats. Certified MRI technologist. Instructor of radiology at the Geisinger Commonwealth School of Medicine. Program director of the Radiology 3D Lab for Danville, Pa.’s Geisinger Health System. Vice-chair of SME’s medical advisory committee, and beginning in May, its chairperson. And if all that isn’t enough on her plate, May also marks the month that Rimini will graduate from Penn State University with a Master of Engineering degree in Additive Manufacturing and Design.

Sarah Rimini and neurosurgeon Sanjay Konakondla discussing Frank Ditaranto’s case, where 3D printed models were used in the diagnosis and removal of a rare cancerous tumor. (All photos provided by Sarah Rimini at Geisinger)

Did we mention that she spends a great deal of her time designing and building life-saving 3D-printed parts?

One in a Million

Consider Frank Ditaranto, a resident of nearby Winfield. On October 8, 2019, Geisinger neurosurgeon Sanjay Konakondla removed a rare cancerous tumor—said to affect one out of every one million people—from the 64-year-old patient’s spine. It was a complicated procedure that involved eight vertebrae, took 19 hours to perform, and could very well have ended poorly had Konakondla not had the opportunity to study a 3D-printed model of Ditaranto’s tumor and surrounding tissue.

The surgery was a complete success, however, and the New York Mets fan can look forward to many more baseball games thanks to three things—Konakondla’s expertise, Rimini’s skill in CT (computed tomography) and MRI (magnetic resonance imaging), and her drive to develop what is now a highly successful medical 3D printing lab.

“I’ve had a bit of an unconventional path to 3D printing,” she said. “Back in 2016, one of our cardiologists attended a conference where they discussed the 3D printing of medical anatomy for pre-surgical planning,” she said. “He happened to have a small desktop printer in his basement, so he asked us to segment the CT images for a patient’s heart. When he showed us the 3D-printed model, we were all blown away by the possibilities. That’s when radiology administration made the decision to purchase a 3D printer for our department. We wanted to see what we could do with it.”


A 3D-printed model of a four-day-old patient’s heart showing a vascular ring malformation.

As it turns out, the answer was “quite a lot.” Rimini’s department currently has seven 3D printers, ranging from industrial-grade, multicolor inkjet systems to more basic FDM (fused deposition modeling) and stereolithography printers. She said the four different technologies—vat photopolymerization, material extrusion, material jetting, and binder jetting—complement one another while giving her department the flexibility to print a quick prototype or extremely realistic models like that used in Ditaranto’s case.

Flesh and Bone

Thanks to the range of different materials available for each printer, she can replicate bone, muscle tissue, and blood vessels, print transparent sections for visibility, or create multi-piece models that can be taken apart and reassembled as needed. “It’s fun to print the flashy, crazy color models you see on the internet, but sometimes that doesn’t benefit the clinician,” said Rimini. “So we try to make it as realistic as possible while giving them whatever’s needed to do their jobs in the most effective manner possible. Ultimately, that’s what provides the best patient outcome.”

Doing so takes much more than a 3D printer and CAD model; Rimini must use her extensive experience in medical segmentation to develop files that are both accurate and printable. As she explained, segmentation is the process of transforming the series of two-dimensional “slices” obtained through CT and MRI scans into realistic 3D reconstructions that can be rendered on a computer screen. This work has historically fallen to radiology technologists in hospitals everywhere, yet she’s quick to point out Geisinger has improved this status quo thanks to a dedicated group of people like herself and the use of advanced medical imaging and simulation software.

A pediatric skull model from a patient with craniosynostosis. A wall thickness map superimposed on the surface of the model shows the thickness of the skull in various regions, allowing the surgeons to plan their procedure.

She and her team have taken that concept one step further by developing what is now a state-of-the-art 3D printing lab. Surgeons and clinicians throughout the Geisinger Health System use the lab’s 3D-printed models to better understand a patient’s internal anatomy and pathology. This allows them to better visualize tumors, congenital defects, injuries, and normal wear and tear, making the treatment of these and countless other conditions much easier.

Physicians can also use the 3D-printed models for surgical practice, allowing them to develop the safest, most effective strategies by operating on life-like polymers rather than human tissue, and doing so well in advance of the actual procedure. And finally, Rimini’s 3D-printed models are used to answer questions from the patients and their families, who are now able to see and  touch affected areas and develop confidence that their prognosis will be a favorable one.

Building on Success

Last year alone, Geisinger’s Radiology 3D Lab produced more than 400 such models, a significant jump from the 30 or so Rimini made in 2017, her first full year working with 3D printing. Examples include 3D-printed hearts that let cardiologists see the size and location of holes and similar defects. Pediatricians have used her models to plan corrective procedures on children with hydrocephalus, an accumulation of cerebrospinal fluid in the brain, and to study ways to install electrodes to treat epilepsy. And as their name suggests, 3D-printed cutting guides increase surgical accuracy while reducing the length of medical procedures.

This molded face/skull phantom is being used for radiography student education. At right is an X-ray of the phantom showing the realistic 3D printed skull embedded inside the model.

Rimini noted that, including the segmentation work, a typical 3D-printed model might take a week to produce. This eliminates any chance of its use in trauma cases, but she sees that changing as the technology improves. “As long as there’s a CT or MRI scan available, we can pretty much print whatever the clinician needs.”

The need for surgical speed is especially important. That’s because the less time a surgical patient spends on the operating table, the greater their chance of recovery. And with medical costs of all kinds continuing to rise, anything that helps streamline such procedures is a boon to patient and hospital alike.

“Educational models for simulation is another important need,” she said. “For instance, we’ve created ‘stop the bleed’ models that show medical students how to assess, pack and suture wounds. We’ve made ultrasound models that mimic a pregnancy, allowing would-be clinicians to practice amniocentesis. And there are trainers available for X-ray students on how to position a person’s skull for improved imaging techniques. All of these make it so that, when they get to work with real patients, they know what they’re doing.”

Sharing the Vision

Unfortunately, none of Rimini’s work is subsidized by health insurers, although they’re beginning to take notice. “It’s following the same trend that 3D imaging did back in the early days, in that healthcare providers had to prove its value before receiving payment for these services,” she said. “Yet we and others like us are providing information to a national registry that clearly illustrates 3D printing’s usefulness. I expect it won’t be long before we achieve AMA [American Medical Association] Category 1 reimbursement certification.”

Sarah Rimini, certified MRI technologist, instructor of radiology at the Geisinger Commonwealth School of Medicine, and program director of the Radiology 3D Lab for Geisinger Health System.

Until that day, Rimini will continue to push the envelope. She said she’s always on the hunt for more realistic materials, hopefully at a lower cost than what’s currently available. The lab has begun casting parts in liquid silicone rubber (LSR) using 3D printed molds as well as over-molding 3D-printed bone, a process that provides “very realistic” results. And she continues to invite others to the lab, sharing information and spreading the good word about medical 3D printing.

“I’m part of a tight-knit group of point-of-care manufacturers across the United States and we all bounce ideas off one another,” she said. “It’s a very sharing, very helpful group of individuals. In fact, they played a role in how I got started with 3D printing—a dear friend of mine is a biomedical engineer at Mayo Clinic and they let me come out to observe their work in this area. Before COVID, we were returning that favor by allowing other medical professionals to visit us and basically just hang out. We’d show them what we’ve learned so far and share the pros and cons of our way of doing things. I’ve also been speaking about our experiences at different conferences since 2017—now that the pandemic seems to be winding down, I look forward to doing that again. With all the new people coming into it, the industry is blowing up like crazy.”

As noted at the beginning, Rimini has a lot on her plate. Given her now extensive experience in 3D printing and what is already a heavy workload, it’s interesting that she decided to pursue a master’s degree in additive engineering. Said Rimini, “I came into this via an unconventional path. I already had a good handle on the medical side but still had a lot of questions about the engineering aspects of 3D printing. Penn State was the first in the country to offer such a program. I knew that I’ve been very fortunate to have such a cool job and saw it as a great opportunity to broaden my knowledge.” She laughed. “Now that I’m done, I’m not sure what I’ll do with all my spare time.”

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