The fusion part itself can be made small as far as I know but the shielding and power requirements would be hard to miniaturize with current technology.
But, with out of the box thinking and developments in technology it might be possible in the future to make this small.
Off the top of my head I can think of a few things that might help but those things are a little unconventional and not publicly tested at this time. But, yeah I would say it is possible to make this small.
