.gi is similar to .iso/.bin, but not quite. I once saw a conversion utility somewhere, but I forget where. Maybe someone can provide some info on this.
This might convert it.
YES You Can Some PPF Patches are Made for the GI format, There are many on their site, Usually if its a split GI apply the Patch over GI #11, Adrenalin Patcher goes the same way usually the patch routine is in the GI #11