Create DRR image from Chest CT scan

(Sumedha Singla) #1

Hi everyone,

We are trying to convert 3D volumetric CT images to chest Xray (for a sake of comparison with another dataset). We use this example:

The projection results in radiography-looking images but it is visually different from what we expected. Here is an example of what we get:

and example what we thought we can get:

I think we are missing some transformation on intensity right before the projection and I don’t what should be. I searched for it and I found this paper:

Is there any transformation on the intensity of 3D CT image that results in 2D projection looking more like chest Xray? Is there anything like that paper implemented in ITK?
Also, if someone can provide some insight into how to use the available options with the GetDRRSiddonJacobsRayTracing method.


(Matt McCormick) #2

Hello @sumedha_singla ! :wave:

It looks like a good start.

The X-ray example looks to have more soft-tissue content from the shoulder, etc. So, beam path selection and interrogated volume selection may help.

Also, Siddon-Jacobs projection is also available in OpenRTK:

which has more configuration options.


(Sumedha Singla) #3

Hi Matt,
Thank you for your prompt reply. You are the best. I will look into your suggestion and post any followup question.

(Sumedha Singla) #4


Can you please elaborate on interrogated volume selection. Also, I have build OpenRTK. Can you please point me to the specific filter that provide this functionality. Meanwhile, I played around with the example in ITK filtering: “DigitallyReconstructedRadiograph1”. Its looks very similar to InsightSoftwareConsortium/ITKTwoProjectionRegistration/blob/master/test/GetDRRSiddonJacobsRayTracing.cxx
But there is no option to choose projection angle. How can we provide projection angle in “DigitallyReconstructedRadiograph1” example?


(Matt McCormick) #5

That is, are the rays passing through the muscles in the shoulder, for example?

Look for examples that use rtk::ForwardProjectionImageFilter, e.g.

RTK is recommended for the most flexibilty.