I had my Aero Ektar checked by the nuclear medicine department at the local hospital and got similar results. Just for curiousity they also tested the lens in the home made box I constructed and it blocked all measurable radiation and so that is what I store it in.
What is it? A 6"x6" x6" cardboard postal carton lined with pieces of "Wonderboard" a cement impregnated fiberglass backing left over from when I installed a tile floor in the kid's bathroom.