Medical 3D Printing

What is medical 3D printing?

Medical 3D printing is increasingly deployed in both clinical and research-based healthcare activities. It involves the creation of physical replicas of anatomical structures using 3D printing (also known as additive manufacturing) processes. A digital computer model is developed to describe the structures to be printed, where patient-specific models for 3D printing are derived from 3D imaging processes such as MRI and X-Ray CT. Small (even single unit) batches can then be manufactured due to the flexibility, speed, and relatively low-cost of the 3D printing process. The models themselves facilitate hospitals and other point-of-care (POC) organizations in planning surgeries, and to serve as an aid for teaching or explanation of complex medical concepts, for example to a patient due to receive surgery.

What are the benefits of medical 3D printing?

The ability to visualize and explore complex anatomy as a real three-dimensional object affords medical professionals with a luxury of decision support not previously available. In a clinical setting, the 3D printed models provide opportunity for increased comprehension of anatomical and pathological structures. Models serve as convenient tools to trial the placement of implants and other medical devices, and to envisage surgical activities. Advancements such as multi-color and multi-material printing can also help to better simulate the surgical environment for pre-surgical planning and intra-operative reference. These models offer a dynamic complement to on-screen visualizations to build confidence in healthcare decisions.

For medical device manufacturers and research-based healthcare activities, medical 3D printing can provide an economical tool for progressing iterative design or process improvements due to its capacity for rapid prototyping. 3D printing also has the potential to provide an early means of validation of in silico trial outputs. With these tools, greater confidence can be gained in new developments before expensive physical testing or in vivo studies are deployed.

How does medical 3D printing work?

To develop a patient-specific 3D print, digitization of a patient’s real anatomical structures must first take place. This method leverages 3D scanning techniques such as MRI, X-ray CT or 3D ultrasound to produce a volumetric image of the anatomy. The images must be labelled, via a process called segmentation, to isolate structures of interest and develop a 3D computer model. The techniques used here are highly varied depending on the scanning modality, anatomical subject, and image quality. Traditional approaches require significant time and expertise but programs with advanced segmentation capability such as Simpleware software can expedite this process.

The 3D models, which may be multi-part, are converted to a series of surface meshes and prepared for 3D printing through the addition of connectors and surface colour information. The surfaces may also be partitioned to allow disassembly of the resulting print, making it easier to view pathologies or structures of interest. The surfaces are finally exported to the 3D printer, typically as STL files for interpretation by the printer software, which adds support material and calculates and executes the printer head paths needed to layer material and reproduce the computer model as a physical object.

Where and when does medical 3D printing fit in the product portfolio?

Medical 3D printing currently fits into the Synopsys product portfolio through Simpleware software products that carry FDA 510(k)-clearance and CE marking for point-of-care (POC) uses. The software enables users to import and process patient-specific images, add landmarks and other measurements, and combine anatomical image data with CAD-designed models. Files can be exported to compatible and validated 3D printers for manufacturing. These models are cleared for use for diagnostic purposes in the field of orthopedic, cardiovascular, and maxillofacial processes.

Going beyond medical 3D printing?

As well as providing a straightforward and accurate workflow for exporting models to 3D printers, Simpleware software is also used to prepare models for further CAD design work, such as for medical device manufacturers carrying out implant analysis and iterative design. In addition, models may be converted into volume meshes for Finite Element Analysis (FE) and Computational Fluid Dynamics (CFD) simulations of physical forces such as implant loading. In combination with a variety of automation strategies, this provides an opportunity for in silico trials.

Putting Medical 3D Printing into Practice

3D LifePrints use Simpleware software as part of services for providing 3D anatomical models for clinical situations. For example, models have been used for looking at liver tumors and potential radiation treatment methods. The 3D printed models provide an additional option for clinicians to better understand patient anatomies prior to treatment.

Steps:

1. Patient-specific MRI data were obtained
2. Scans were imported to Simpleware software for segmentation of the liver
3. Files were then exported for further processing to mimic different-sized tumors, including different chambers for holding radioisotope samples
4. The processed model was 3D printed using a PolyJet machine
5. The 3D printed phantom was scanned (Phillips PET/CT) in the correct anatomical orientation and used as part of a surgical plan
6. Clinicians used the measured dosage and known cavity volume for a patient to estimate the surrounding exposure on the liver