Iodine capsules and radiophobia

[David Scherer <scherer@uiuc.edu>]

I recall reading about ten yr ago that up to 10 percent of the I-131
activity in a gelatin capsule can pass the capsule and appear as surface
contamination.  I don't remember the source, but the proportion struck me
as pretty substantial, especially when the dosage to one pt may be 200-300
mCi.  Not all of this will vaporize, but I do not believe it is rampant
radiophobia to be concerned of internal contamination in this situation.
Especially when the technologist is administering doses to many patients.

On another point I will be more blunt.  The assertion that patients are not
harmed by therapeutic dosages of radioiodine is pattently absurd.  These
treatments produce NONstochastic effects on thyroid function.  That's why
they are administered!

As we discuss paradigm shifts in low-dose radiation response let us keep
some perspective.  Large doses of radiation (tens of rems) or high body
burdens of RAM (tens to hundreds of millicuries) are clearly hazardous.
The questions are in millirem and microcurie ranges.

Dave Scherer
scherer@uiuc.edu