Printing in Three Dimensions

When it comes to 3D printing in healthcare, long gone are the days of rustic, stiff protocols that offered more novelty than real-world use.  Next generation 3D printing technologies are helping medical providers, especially radiologists, revolutionize everything from facial transplants to cardiovascular surgery.

“3D printing has been an opportunity for radiologists for more than 10 years,” said Frank Rybicki, MD, PhD, chief of medical imaging at Ottawa Hospital and former director of the Applied Imaging Science Laboratory at Brigham and Women’s Hospital in Boston. “But it’s mostly in the last five years that the technology has been more available to us and people have become more aware of what a 3D printer can do.”

Rybicki says the value of the technology lies in what it produces—a physical object you can hold.

“Whether it’s a heart or a piece of bone, giving a surgeon the ability to hold the body part in their hands before a surgery is a huge benefit to them when it comes to planning and preparation,” he says.

Bryan Pukenas, MD, an assistant professor of radiology at the Hospital of the University of Pennsylvania, thinks 3D printing will place radiology at the forefront of patient care through education and innovation.

“In terms of education, for the first time patients can ‘hold the disease’ in the palm of their hands,” Pukenas says. “For example, a patient with a brain aneurysm typically undergoes a CT angiogram for diagnosis and treatment planning. At the same time, clinicians can take that model and simulate treating the aneurysm, which may decrease complication rates related to treatment.”

Pukenas says that as a radiologist, he’s most excited about the innovative potential of 3D printing.

“Our team performs many biopsies for our oncology colleagues since tissue sampling is paramount for tailored cancer therapies, and despite our relatively high yields with biopsies, we saw a need for a better needle design in order to make our yields higher,” he says. “Our team was able to design and print a prototype biopsy needle both quickly and inexpensively. That design is now protected with a provisional patent, and we are in preliminary talks with a company interested in this design.”

Another benefit of combining radiology and 3D printing, Rybicki notes, is the ability to have a surgical reconstruction piece prepared before a patient goes into surgery and is placed under anesthesia.

“Previously, the measurements and fitting of the reconstruction piece had to be done while the patient was under general anesthesia,” Rybicki says. “But now, the measurements can be done before surgery and the new part constructed and ready before surgery begins, saving the surgeon a lot of time and that means less time for the patient to be under.”

The future for 3D printing is wide open and Pukenas sees the technology as another way for radiologists to add value in the modern healthcare environment. He uses fetal ultrasound as an example, citing 3D printing’s ability to demonstrate a defect in the fetal spinal canal.

“The 3D ultrasound images could be used to create a life-sized printed 3D model of this individual patient, and surgeons could perfect each step in this particular repair over and over again. Most likely this would decrease operative time and potentially decrease fetal and maternal surgical complications.”

Growing interest

The buzz building around 3D printing in radiology has generated interest in both the broader public and within the radiology community.

“I teach 3D printing workshops at RSNA and this year’s workshops filled up quickly,” Rybicki says. “The technology is becoming much more commonplace and it’s capturing the public’s imagination. It definitely has a place in radiology as the software and the ability to print with less expensive machines becomes more available.”

3D visualization of medical imaging data is routine today. 3D printing is simply an extension of that: instead of printing a 3D picture, it is possible to print a 3D model. The value of 3D printing isn’t necessarily for the radiologists, but for the physicians on the front line of patient care, says Dominik Fleischmann, MD, professor of radiology at the Stanford University Medical Center and director of the medical center’s 3D and Quantitative Imaging Lab “The capability of 3D printing­—like imaging based information in general—best serves the clinical users.”

Fleischmann notes that as surgeons and interventional cardiologists were first interested in the ability to print anatomical structures, they started to look around at what was technically possible, and what 3D printing would cost.

“The one thing that we learned when we first tried to print objects in 3D was the printing capabilities and range of costs is huge,” he says.

Fleischmann says that on one end of the spectrum, the commercial end, the printers are so advanced that they are able to print multi-textured structures that are pliable and more life-like.

The technology has been around for years for rapid prototyping and many other technical and commercial applications. It is very mature. On the other end of the spectrum are the more cost-effective models that came out more recently at a very low consumer prices.

“We purchased low-cost printers with less high-tech abilities, but it allowed the lab to offer more opportunities to experience the process to their clinicians,” Fleishmann says.

For more sophisticated models, Fleischmann said the lab prints off-site.

“The learning curve really pertains to generating the digital models out of the image data—that’s where the radiologist and technologist expertise comes in. Once a digital model is generated, it can be printed on any printer,” he says.

As the printers themselves evolve, so too does the software applications used to produce the models, says Shannon Walters, a colleague of Fleischmann who serves as the chief technologist at the 3DQ Lab at Stanford.

“The software vendors we are currently using routinely for 3D image generation also provide tools to create a mesh model out of the image data that most printers can take and do something with,” Walters says. “With the 3D lab here, we apply 3D processing technology routinely for clinical care, but now we can extend this and make the mesh model, and then print the object. The skill to do that is really the integration of understanding the anatomy, pathology, and what a surgeon or interventionalist wants to see – or rather hold in his or her hand.” Walters adds that these are not routine cases, but situation where the anatomy or pathology are complex.

Printing the future

Looking forward, Rybicki sees 3D printing moving out of academic teaching hospitals and labs and into broader medical practices.

“It’s a very exciting time,” he says. “In the future, 3D print labs will exist within radiology departments as part of academic and private practices as more data come out and experience is gained. There’s no reason it will not become mainstream radiology.”

A potential roadblock in advancing the technology to more providers and hospitals is funding—reimbursement to more specific.

Adopting a common nomenclature and reporting methods are the first steps in Rybicki’s opinion.

“Individuals who now embrace the technology also need to commit to better, more consistent reporting of the materials, hardware, and cost, both money and time, for individual models. Armed with consistent data, larger trials can be explored to demonstrate the benefits,” Rybicki said, adding that Brigham and Women’s introduced a standard reporting template that included printer hardware, materials, cost and print time.

“Industry in 3D printing is just not used to medical reimbursement issues,” he said. “[If they were reimbursed] more radiologists would certainly participate.” HI