A few summers ago, we had a heatwave and drought, and ants invaded our kitchen. Naturally, we called the exterminator guy. I don't like having insecticides sprayed inside the house, but this was out of control. He came like a dozen times, each time spraying stronger chemicals inside and out, and he didn't even slow them down. From my research online, I found oil of cloves
suggested, so I tried it, putting a few drops in a spray bottle of water and sprayed it in all their entry paths. It stopped them immediately! You can watch them, and where they walk across a sprayed area, it seems to burn their feet, and then they crumple up and die. I'm not saddistic, but I enjoyed watching the li'l invaders die because I had battled them for so many weeks!
So now, a part of my cleaning routine is to finish up with a light mist of oil of cloves spray over everything in my kitchen, window sills, counter tops, floors, wall, everything, and a bonus is that the room smells wonderful.
Anyway, I said all that to say this. They must have a path to the scanner. I would spray all the surrounding area. The idea about putting them in the cold sounded good, but they'll come back unless you've treated the area. You can buy a bottle of clove oil at your health food store. Hope that helps.