If anyone is that concerned about their damn thyroid, just go get a CT with contrast. That will load you with enough iodine to protect you for at least 6 weeks. But really, is your most pressing concern in this situation the possibility of getting thyroid cancer in 15 years? (BTW, if you have to get a cancer, let it be thyroid...it's pretty benign. I'm more worried about the other effects of radiation.
) It's not Armeggedon.