How to use brain ct images to build models in geant4

Hi geant4ers
I have recently been working on an experiment to detect the energy deposition of particles in the brain and the location of the particles. I originally used an external OBJ file for the brain modeling. But after reading a few papers I realized I should actually use CT images to build the model. Because this is more convincing. So I would like to ask some experts how I should use CT images to build the model.
Thank you all for your answers, your guidance is very important to me as a newcomer.

You may have a look at the example extended/medical/DICOM to build a Geant4 geometry out of a DICOM CT image file

Dear arce:
You’ll never believe how important your advice is to my current experiment. As a beginner I really didn’t even know this example existed :joy: :joy: :joy: :joy: :joy: