I try to enable the vtkDICOM module in VTK 8.2.0,  I set the Module vtkDICOM option for the cmake cache:
cmake -D Module_vtkDICOM :BOOL=ON …/vtk -source
then I got the warning:
CMake Warning:
**      Manually-specified variables were not used by the project:**
**           Module_vtkDICOM**
does anybody know how to handle this?
thanks