Yes, Terminal 4 is now using body scanners at the centralised security.

They are also being progressively introduced to the other terminals - they can be found at the "hub gates" in T1/2/3 now and will be rolled out across the smaller gates as time goes on.

At a cost of $180k USD per machine - I imagine it'll be a slow and painful rollout (92 gates across T1/2/3!)