Re: Iodine therapy patients (again) -Reply

[Ccja@aol.com]

Well, small children could be at distances considerably less than a meter
from the patient, for extended periods of time. In conjunction with that I'd
like to ask if anyone has considered the question of what dose might be ALARA
for children. The 500 mrem figure assumes an adult's exposure. The ICRP,
either in #60 or in the Publication on biomedical research (#62?), holds that
children are at least twice as  stochastically radiosensitive as adults. It
would seem to be the better part of valor, from the risk management POV, to
issue instructions sufficient, at least, to limit the potential dose to a
child to no more than half that of an adult. Note that when the ICRP says
"child" they mean through the teenage years. Note, too, that the regs limit
childrens' occupational doses to one-tenth those of adults; which value is
probably quite arbitrary.

There are other issues associated with the early (i.e., immediate) release of
these patients, which I don't think I've seen addressed. For one, since
they're off their thyroid meds, they tend to be chronically queasy. Consider
the consequences of a 150mCi emesis of warm, acidic material, particularly in
a confined space with poor ventilation. Diagnostic quantities, and possibly
more, would be airborne. Note that the ICRP halftime for residence in the
stomach is 0.5h.

chris alston
ccja@aol.com