There are a number of screening models that combine various systems. One of them utilizes a full-body scan but also does a trace. A passenger pushes a bar, and it detects that, and thre's a vapour down at shoe level to determine whether there are any explosives carried in their shoes, as in the case of the shoe bomber Richard Reid.
We believe that type of technology, with some improvements, is probably what we're looking at, going into the future.