Yes, as the Vita isn't region-locked for retail carts (for example, you could import a JP-only Vita game for your NA Vita and it would still work fine). The issue comes with DLC (as it is tied with the region the game is linked to, so a JP only game would only have its DLC workable if you are on a JP PSN accounts).
With the Ratchet Collection though, it should be no issues at all; if there is a patch, then you will get it and I doubt a collection is going to get DLC. If you want a retail version (as I doubt the US will have one) or just want to play the game now, then import it .
Thanks man, yeah importing looks the way to go.