RAI treatment and Homeland Security?

I'm going to have radioiodine treatment next week. (100 mCi of I-131.) I was told that border patrol innerstate traffic stations have radiation detectors for terrorists who have been screwing with bombs. I p one from the town where I get my treatment to my house. Does anyone know anything about this? Is there a place that I can register as a patient or an official form I can have my doctor sign? I don't want to be pulled out of my car at gunpoint for being radioactive!!!!!