Good point.

I work a bit with PET-related isotopes, mostly fluor-18 and carbon-11, which has half-lives of 110 and 20 minutes, respectively. You gotta be careful with that stuff, the radiation (β-minus) is pretty dangerous if you're exposed for long (usually there's 5-30 GBq per vial), but again, it's pretty neat that if something happens (you spill something for example), you can just leave the room and clean it the next day without any problems. Overall, there's really no radioactive waste, since after 24 hours it's darn safe (and the FDG turned to sugarwater, literally).