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What to do if your file fails to process on democratiz3D

Dr. Mike

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Occasionally files uploaded to the democratiz3D service for conversion to STL will not process correctly. What should you do if this happens? Usually these failure are due to one of two items: 1) There is some problem with the uploaded file, or 2) The uploaded file is simply massive (i.e. head to toe thin cut CT). 


If you encounter a problem with processing of your file, the first thing to do it check the quality of your input file. See my earlier tutorial, Choosing the Best Medical Imaging Scan to Create a 3D Printed Medical Model, if you want more details.


1) Check the modality. Did you upload an MRI when the operation calls for a CT?


2) Check for artifacts. This will often cause the model to have obvious deformities. The most common is beam hardening from dental fillings, as shown below. Normal teeth without fillings are on the left, and teeth with metal dental fillings are shown on the right. Unfortunately, you can't make an STL file from data that isn't there. If you scan has lots of artifact, you can either choose another scan or go through the laborious process of fixing the artifacts manually after the model is created.



3) Reconstruction kernel. This refers to the edge enhancement or sharpening algorithm that was applied to the scan images after they were acquired on the scanner. These are often done on dedicated bone or lung CT scans to enhance the contrast as make it easier for the radiologist to see subtle findings, like hairline fractures. Which the edge enhancement algorithm (or sharp kernel) as shown on the left below makes the edges easier to see, it also results in a speckled or noisy appearance of the tissue. This can confuse the algorithm because some very high intensity spots may look like bone. If your file is failing and you are using a sharp kernel series from you scan, consider using a different series that has a smooth kernel, such as shown on the right below. If you must stick with the sharp kernel, increase the threshold level to reduce the amount of "sand" in your output file and increase the changes of a successful processing job.





Hope this helps,


Dr. Mike

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