In 2002, I had the body mechanics do a triple bypass on my inside plumbing. After I recovered, the cardiologist decided to run a "Thallium Stress Test" (which was actually done with technetium). They injected me with radioactive whatever, ran the tests, and warned me not be too intimate for about 12 hours.
I had my Korean War era Geiger counter with me, but didn't have the guts to take it into the hospital. I've created havoc with it (such as in a supermarket after Chernobyl) in the past and didn't want to deal with the inevitable hassles. So, I get out to the car, turn it on, and find that it's pegged on the highest scale. Nifty.
Some of my customer are conveniently located near the hospital. Technicium 99 has a half life of 6 hours. If I was going to terrorize my friends and customers, I would have to move fast. It was lots of fun, but I also learned a few odd things about people and radioactivity.
When I fired up the Geiger counter, many members of the younger generations didn't have a clue what the clicking meant. Few had even seen a Geiger counter. Apparently, they don't teach radioactivity in the skools any more. Most of them asked "what's that noise"? Duh.
However, anyone over about 50 knew exactly what the high rate clicking meant and usually jumped back several feet in horror. One older gentleman nearly fell over backwards in his chair because he couldn't get out of the way fast enough. The baby boomers all had some experience with radiation in the skools during the early daze of the cold war. The younger generations have not.
Incidentally, before terrorizing my friends and customers, I did a rough calculation of the exposure and found that I had received a dose of roughly a months worth of allegedly safe radiation exposure (500 milli-rems). No way is a few minutes of that going to adversly affect anyone. (5,000 milli-rems/year is considered safe).
I also had a substantial number of people ask me "Why do you have a Geiger counter". I didn't catch the significance of the question until somewhat later, when I realized that they suspected that I was conducting dangerous radioactive experiments at home.
One problem with radioactivity is that the units of measure are generally confusing to the GUM (great unwashed masses). I had no idea if 74Kg of natural uranium was trivial or devastating until AFTER I ran the calculations and comparisons. Most fail to distinguish between ionizing and non-ionizing radiation. I get that all the time in the wireless and wi-fi newsgroups. I suspect the media has a similar problem.
Ominous looking sign on my wall: "Danger 1,000,0000 ohms" with a 1M resistor taped to the sign.
Light reading:
The book is well worth reading, even though it's full of intentional inaccuracies and omissions intended to prevent other aspiring Scouts from trying to duplicate the same experiments.