Embedded Files
THE PROJECT
This was done for a client in the medical device arena who works as a doctor in clinical cardiac electrophysiology. The task was to reconstruct a series of DICOM scans obtained through computerized tomography (CT) into an object fit for additive prototyping. The purpose of the experiment was to test the integrity of additive solutions in producing replacements for unique bodily internal objects that can be transported through a medical catheter made for this purpose. The catheter is meant to accept this compliant additive geomtery in a propritery way using a hub/spoke architecture which I describe in further detail below.
The first phase of the design included 3d reconstrucution from CT scans and DFAM mesh processing in order to manufacture prototypes on an FDM 3d printer. The post-processsed 3D file is shown to the right and an image of the pre-processed file is shown further down the page in yellow.
A video representation of the post-processsed model used for pototyping
Image of the 3D Dicom reconstruction shown with bodily attachments
Above are some of the raw CT scans in image form. Each layer of 6 images represents a different cross-sectional axis. To properly reconstruct a 3D model from scans such as these, all axes are needed. Overall there were 575 Dicom files: each representing a certain cross section in either the x, y, or z axis.
Above are sliced cross sections of the reconstructed body showcasing the geometry's internals. The reason the wall thickness looks organic/arbitrary is because it was calculated based on topological features of the geomtery rather than being thickened and uniform based on the freeform outer surface. This gave more strucutral integrity to the model when additively manufactured in TPU and medical-grade Nylon.
PRE-PROCESSED MODEL
To the left is the reconstructed 3D model that came straight from the CT scans. As you can see, there are many portions of the geometry that are not suitable for manufacturing. I eliminated this extraneous topology, closed any unatural holes in the geometry, smoothened surfaces that were otherwise too rough, and finally healed the mesh before getting the 3d-printable result that you see below.
MODIFICATIONS FOR CATHETER
To the right is a depiction of changes that the client asked for in optomizing the model to be transported through a catheter. The grey geometry shown on the underside of the reconstructed body was to act as a hub and the surface that this hub connects to was to be removed. The hub would then connect coaxially with a spoke architecture to the orifice of the reconstructed body which is now open on one end.
The idea with this design change was to use the hub and spoke model to pull the entire geometry into a catheter, thereby, in theory, transporting the reconstructed bodily geometry into the patient, for whatever use case the doctor might have.
Above are images of the 3d printed prototypes. The leftmost image is a print in Nylon, the middle is standard TPU, and the right is a cut cross section of a separate cut open Nylon print.
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