CMTK can binaries can be downloaded from the project homepage and are generally the way to go. On a mac we currently use the dmg installer for macosx 10.6 NOT macports.
However you may also want to compile from scratch. On a mac this looks like this:
Prerequisites
Get the source
Use svn (see NITRC page) to get the official source or use git to clone my unofficial github mirror (daily updates) :
git clone git://github.com/jefferis/cmtk.git # public repo, read only
to clone a git mirror of the svn repository.
Compile
cd cmtk/core mkdir buildv31 # I normally make a build directory for each public release cd buildv31 cmake -C ../config/OSX-10.8-x86_64.cmake .. # -C [config script] <cmtk_source_root_dir> make -j 8 # -j 8 uses 8 threads if you are in a hurry sudo make install
Note that OSX-10.8-x86_64.cmake config should work for macosx >10.6
Done.