Radioactive after FDG injection????

You are right to be concerned. However, If your friend sits 2 meters away from you after the injection of FDG, their dose will be greatly reduced. The FDG does have a half life of 2 hours (well, 110 minutes) and the dose will be half decayed after 2 hours. But-- you also excrete the FDG in your urine. So more than half of it is gone from your body after 2 hours, if you urinate. I just checked a patient last week 2 hours after her FDG injection, and she was giving off a little radiation, but not a lot more than background. You do want to be careful around pregnant women, because it's always better to be safe than sorry. Children and fetal tissue are more sensitive to radiation (because their cells are dividing faster than older people's.)

Do you know how much FDG you are getting? The dose can range from 10-20 millicuries, which gives a bystander a much different dose.

Hope this helps.