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.