Part I – Voxel Printing
(photo above: Voxel Printed Tractography with Brain)
The call for 3D printing in healthcare is never mellifluous nor easy to celebrate, because the demand for a pre-surgical 3D printed model is always a harbinger of a serious disease and a complicated surgery. As I write this blog, I’m sitting in the last of 3 surgical conferences on Friday, March 16th, we are discussing the pandemic protocols being enacted. These conferences are intended to review the surgical cases for the coming week, the plan, in each surgical discipline, is to prioritize the most critical and complex cases to lessen the load of surgeries and free up nursing staff. As a result, my 3D printing services are in high demand to assist with these cases on the front end as the pandemic protocols wash over my hospitals.
However, this blog post is going to avoid the prevailing Damocles and focus on the promise of exciting technologies poised to positively impact society.
Currently, I am a Clinical Design Researcher at the University of Colorado Anschutz and the CEO of MIX Surgical Technologies. MIX provides ultra-high-resolution 3D voxel printed pre-surgical planning models and computational analysis for surgeons and healthcare professionals. We are in the early stages of our first fundraising round. My journey into biomedical 3D printing is quixotical and as a result, the technologies I bring into the conversation are different, disruptive, and redefining what is possible for improving patient care.
As an Architect, I see the entire problem of biomedical 3D technology differently. The tools I use are mostly design and engineering-based and I am much more comfortable designing houses in Aspen, Aerospace buildings, and O.R’s than designing the equipment inside. However quixotical it may seem, Architects have a long tradition of coloring outside the lines. As a child, I grew up near Spring Green Wisconsin and Taliesin, the summer home and school of Frank Lloyd Wright. Mr. Wright is famous for redefining what it meant to be an Architect by applying the concepts, technology, and techniques he used in his buildings to Fashion, Jewelry, Sculpture, Industrial Design, Structural Engineering, and farming to name a few. Taking inspiration from Mr. Wright, I approach biomedical 3D through the same lens by applying the concepts, techniques, and technology we use to design skyscrapers to creating better 3D technologies for pre-surgical planning.
“So now I know everything anyone knows.
From beginning to end. From the start to the close.
Because Z is as far as the alphabet goes.”
Then he almost fell flat on his face on the floor
When I picked up the chalk and drew one letter more!
A letter he never had dreamed of before!
And I said, “You can stop, if you want, with the Z.
Because most people stop with the Z.
But not me!!!
In the places I go, there are things that I see
That I never could spell if I stopped with the Z.
I’m telling you this ‘cause you’re one of my friends.
My alphabet starts where your alphabet ends!”
Dr. Suess – ‘On Beyond Zebra’
CREATIVITY> DECODING> METHOD > PROCESS
As an Architect, the first question I asked when I began to study surgery was simple: Why are we still relying on 2D images to represent the 3D human body? Some might say it’s because of an indelibly ingrained process that has been the primary visualization modality over a hundred years. For much of the last century, 2D images were considered ‘the Z’ until 3D printing came along bringing with it a whole new alphabet that includes letters from Mechanical Engineering, Mathematics, Design, Computer Science, and Digital Media. As a result, we have medical software with .STL export functions and Doctors 3D printing in their offices on desktop printers. In other words, Doctors are beginning to speak with this new language.
We look for alternative ways of representation that will feed, rather than interrupt, our thinking process. They become sources of ideas that help us and our collaborators see, and react to, the thinking behind the design
Today, most, if not all working on biomedical 3D printing and 3D technologies are healthcare professionals and biomedical engineers. Seeing as the goal of biomedical 3D technologies is to create a tool customized to precise, complex, and unique disease, having the end-user (surgeons) involved in the process capitalizes on the greatest promise of these tools, scalable customization. However, most if not all biomedical 3D technologies are only just scratching the surface of the possibility of what can be created and consequently the potential to heal. Continuing to operate with out-of-the-box 3D biomedical software, that relies upon the absurd process of segmentation limited to creating what Neri Oxman would call ‘Discrete elements with distinct functions, constitutes stopping with just the ‘A, B, C’ of this new 3D language’. In this vein, I want to introduce three new letters, the ‘D, E, F’ if you will into this new lexicon:
1. Voxel Printing
2. Parametric Design Software
3. The Surgeon/Designer Interface
1. Voxel Printing
What’s a voxel? Well, think of it as a three-dimensional pixel. In fact, the word voxel is short for volumetric pixels. Much like a pixel, which describes the attributes (like color) of an element within a larger composition (an image); a voxel can describe attributes about a physical location within a 3D volume. These attributes can include information about their material properties, density, color, and more.
Voxel printing is one of the most exciting advancements in 3D printing in the last 10 years and the best example of design at the intersection of computation and multi-material 3D printing. Voxel printing is a technique using a polyjet printer, which is a printer with multiple print heads depositing droplets of resin that get cured with UV light. A polyjet 3D printer works similarly to the common inkjet printer. Voxel printing allows us the ability to control every droplet, varying material properties and colors at a resolution of ~15 microns.
At MIX we will be voxel printing all of our pre-surgical models. This is important for three main reasons: 1) Gradient; modeling soft tissue that changes density and color point by point can be printed in one continuous gradient. 2) no file size limitation, which means there is no limit to the topological complexity of the anatomy. 3) No segmentation required; voxel printing allows us to print directly from the input data, most commonly DICOM stacks. This last point is the most important, eliminating segmentation means that we have significantly reduced the time to print, eliminated the opportunity for human error, and increased the amount of data being transferred into the 3D printed models.
‘Why is the best fruit always forbidden’ – Cardi B
Voxel printing has always been around but you probably haven’t heard of it before. Despite the fact that voxel printing is the native way a printer functions, up until 2018 it was an inaccessible feature on most printers. Objet was one of the companies to start making voxel prints as far back as 2011. Panagiotis Michalatos and Andy Payne were two of the first to experiment with the technology. Panagiotis, an Architect, and Professor at Harvard University were researching the idea that software, and the process of making therein, can change your intuitive understanding of the problem. Early on these problems revolved around Structural and Mechanical engineering and desire to think about structure as a distribution of material properties rather than an assembly of parts. The results of which have proven to be the same, though, the approach and processes are novels, which brings forth a plethora of benefits alone by simply being able to think differently.
Today, Stratasys is the only company with the commercial capability to voxel print and I anticipate many other companies will come online with the capability soon. One other limitation stands: There is no commercial software that allows for modeling, editing, and file creation. Few have been able to figure out the process as it requires custom build software and a grassroots process requiring knowledge of coding on multiple software platforms. As a result, I have filed a patent-pending method for voxel printing from DICOM files and we are working hard to bring voxel printing to the market in the form of a service bureau.
Think about the implications. Modeling Tissue Compliance for better device placement, Modeling Bone Density for lower risk pediatric cranio procedures, visualizing microvasculature to eliminate cutting small veins during liver dissections, anatomical models with an overlay of analytical dynamic data, and patient-specific valves that avoid paravalvular leakage. All done without segmentation, without human error, and completed in a fraction of the time of the models currently being created.
Stay tuned for my next article exploring the (2) Parametric design software!
About the Author:
Nicholas Jacobson is a practiced architect and designer; he designs buildings for the aerospace industry, OR’s, high end residential, and off grid structures in extreme environments. He has been 3D printing since 2002 and focused on biomedical 3D printing since 2014. Currently, he spends time working alongside surgeons to find new opportunities for 3D printing and improving patient care. He received a Bachelors in Architecture (Cum Laude) from the University of Wisconsin SARUP and an M.Des (Design Technology) from the Harvard Graduate School of Design.
His work and research have been published in books, scholarly journals, magazines, and newspapers; these include: ACADIA, AD, CAADRIA, Code LA, Huffington Post, Modern Luxury, Nature, New York Times, Popular Science, and Vogue and shown work both nationally and internationally. He has lectured at Harvard University, Stanford University, University of North Carolina, University of Puglia, the University of Denver, and for companies such as AutoDesk, Zaha Hadid Architects, Thornton Tomesetti, Stratasys, and Trimble.
About MIX Surgical Technologies
A biomedical 3D printing and design studio. Focusing on patient-specific 3D printed models for surgery. We use advanced technology in modeling, segmentation, and printing. This includes multi-material ‘Voxel’ printing for ultra-high resolution functional gradients and multiple data sources.