Error running DICOM example

Hello everyone
Recently I was running the dicom example, but I ran into some problems and I was going to use the DCMTK library to run the example. I downloaded the DCMTK library and installed it under the path /home/dcmtk. Then I added the environment variable with the command export PATH=$PATH:~/dcmtk-3.6.6-install/usr/local/share/dcmtk/dicom.dic (I don’t know if this is the correct way to add environment variables).
After that I started to run the example and the result is in cmake… After that I get this result
– DICOM settings:

    – Configuring done
    – Generating done
    – Build files have been written to: /home/geant/geant4_workspace/DICOM/build
    I don’t know how to turn on DICOM_USE_DCMTK
    So all you experts, I know my question seems silly, but I really need your help, I haven’t worked with Linux before, so it’s hard for me to know what my problem is. I really need your help, even a word would be a great help to me.
    Thank you all.