Software suggestions for FDG-PET z-score

Dear neurostars.

I am looking for a software package that can generate a z-score map/statistical surface projection given an FDG-PET image. More specifically, I am looking for a free alternative to the functionality provided by Scenium: relating an FDG-PET image with some standard FDG-template to create a z-map for abnormality detection. Do any of you have any recommendations? Preferably with some python interface.