3D Printing CT Scans on a Makerbot

Converting a DICOM CT scan to a 3D Stereolithography (.stl) file is a simple process that produces interesting results. These files can then be printed on a 3D printer such as the Makerbot Replicator 2x.  The DICOM files used in this demonstration were used with permission from Dr. L. M. Witmer.

To do the conversion you will need two pieces of software.  The first is InVesalius (http://svn.softwarepublico.gov.br/trac/invesalius) and the second is FreeCad.  Both are freely available under their respective licenses.
Begin by opening InVesalius and click "Import Medical Images".

Then browse to the folder containing your DICOM CT scan files and click OK


InVesalius will import the DICOM Files and display the scan when done.

Now select "Import" in the lower left hand corner.

You will now see a screen similar to the following:

Select "Create Surface" from the left hand task pane and wait a few minutes while it processes.

Once complete you will see a three dimensional rendering of the CT scans in the lower right panel.  You can spin and rotate this model to verify it rendered properly.

Finally, in the left hand task pane expand "4. Export Data" and choose Export 3D surface. Choose a filetype and filename and save.  Note for Makerbot's Makerware program, use the .STL file type.

This particular scan has some artifacts at the bottom that  cause a lot of wasted support structure to be printed on the Makerbot.  To remove these, launch FreeCad and open your file.
Select "Mesh Design" (1) from the drop down at the top.  Orient the model so that you can see the artifacts you would like to remove by using the various view buttons at the top (2).  Now click on your model and the "Cut with Picked Polygon" tool (3) will become available.



Select it and click the points around the object you want to remove.   Now, right click and choose "Inner" and the objects inside your polygon will be removed.

Finally select the "Export a mesh to a file" tool (4) and export your model back to an .STL file and you are ready to load your model into Makerware and print it.