We have a version of the Diedrichsen cerebellum atlas available.
[
afni.nimh.nih.gov]
The Eickhoff-Zilles atlases included with AFNI also have an earlier version of the cerebellar structures from Diedrichsen.
Using regions are similar from these atlases work the same as other atlases. You may want to resample with nearest neighbor interpolation with 3dresample, or use 3dfractionize if you want to preserve partial volumes of masks.