In my watching of TV I recall having seen the first of the images, made by a PET scan, of the active dynamics of the Human brain, at work. I suspect that, since then, they have changed the radioisotope employed, as the original one was a dual photon(*) emitter and it was not the "safest" but the dynamic pictures of the brain, actively thinking, were really neat to watch, and does it ever act fast.
(*)(They used a dual positron(?) or photon(?) emitter which they later found out had some rather not so nice side effects)
Do they still have the ability to generate active (visually real time dynamic) brain scans using PET's?