Answer to Question #4684 Submitted to "Ask the Experts"

Q

I recently started working as a traveling contract nuclear pharmacist. I packed my whole-body exposure badge and ring badges in my checked in baggage for four flights last month. When my readings came back from the vendor for that month's badges, they were much higher than usual. My usual exposure for rings is about 1,000 mrem/month and whole body is 20 mrem/month. The badges that went through the security checks (and were worn during the month for my usual work duties) were 2,000 mrem and 454 mrem, respectively for the month. I have seen estimates that range from 0.1 mrem to 50 mrem per bag per screening.

How much should I ask my vendor to subtract from my month's exposure so that the numbers reflect my true work exposure?

Or, should I just take the last six months exposure, divide by six, and tell my vendor to adjust my month's exposure to reflect that number instead of the baggage security induced artificially elevated exposure value for the month in question?

Of course, from now on I will carry my exposure badges with me as carry-on luggage. That exposure is much, much lower, right?

A

It is difficult to say how much radiation exposure should be removed from the badge. You say that your normal exposures are 1,000 for the ring badge and 20 for the body badge, but you also say you just started working as a contract nuclear pharmacist—so are these "normal" exposures what you have been receiving as a contract nuclear pharmacist? If so, then your suggestion of averaging the past six months would be reasonable.

If not, then we don't know what your normal exposures were/will be. Based on the literature available from companies selling the checked luggage screening units, it seems unlikely that your ring exposure would have doubled and your body badge exposure would have gone up by an order of magnitude. Plus, each should have increased by approximately the same amount if the exposure was just due to the screening unit. Based on this, I'm not sure you can legitimately subtract any exposure.

You need to keep a control badge with your badges when you travel. It would stay in your bag while traveling and then be sent in with the badge you wore. This reading from the control would be subtracted from the badge you wore for work. That is the only way to know for sure.


Kelly Classic
Certified Medical Health Physicist