Converting medical scan data into a 3D printed model




In 5 steps:

1.       Get Image Data. Once we have the DICOM data files we will need software to import the files, read them, and convert into a 3d object. We had the sequence of CT scan files with good bones representation of a small dog.


There are other scan files available on the web here we can fine some good ones: http://www.ohio.edu/people/witmerl/lab.htm# from Ohio University. Dinosaur sculls are really cool.

2.       Get Medical imaging Software. Quick search for the program led to ImageViz3D http://www.sci.utah.edu/software/imagevis3d.html package. This software seems to be able to visually display the model in 3d interface, we can rotate and zoom, but the exporting it into an .stl object file produces weird results and files are really heavy.


We will be using a software package called Invesalius available at http://www.cti.gov.br/invesalius/, developed by the Brazilian government and made available for free.
It is available for the Microsoft Windows, GNU/Linux and Apple Mac OS X platforms, and for Mac you can check out a similar package called Osirix http://www.osirix-viewer.com/ which is designed for medical imaging and also available for free.


3.       Convert Imaging Data of Interest in to 3D Object. Once we have the files loaded into Invesalius it shows all the images as a whole, and now we will need to convert them into a 3d object. Invesalius can do it effectively well.


In Invesalius this function is called Create Surface and we can tweak the properties of the Mask range for the various tissues, such as Skin or Bones. There are also preset default Masks, and we will be using their Compact Bone (Child) one, just because we have a young dog.


Press Create Surface and give it some time until it gets created. Under the Surface you can see the surfaces that has been created, so you can hide/see those you will need. Next, under the Export Data, click on the Export 3D Surface and export it into an .stl and give it a name.

4.       Remodeling. We have exported the whole bone structure that will need some remodeling.



There are tons of 3d model editing programs (such as Blender, 3dsMax, Meshlab, Netfabb Studio Basic, and etc.) and we will be using Meshmixer by Autodesk to clean off the model and have only the area that we are interested in.
“As we look closer, it appears there is a deformity (osteosarcoma) at the distal end of the left radius, and the most important parts are the toes through and including the forearm.” – Dr.Prawel.

5.       3D Print. That would be nice to 3d print it with a 3-headed printer could print the hard, soft and water-soluble support at once. However, for the first time we try a quick print using INOVA Chromo Strand filament on a Lulzbot printer. However, it is recommended to use Support everywhere, Fill Density – as much as possible (80% in our case) and High Quality for better prints.



 


After 18 hours we have the following:




And after some post processing, dremeling, filing, and gluing (yes, sometimes the bones are not connected, just like in life) – we have a cute life size 3d printed copy of a bone:




Nik

I am passionate about creating stuff and want to change the world.