Re: Patient Info Following Iodine Therapy

[Ccja@aol.com]

NUREG-1492, "Regulatory Analysis on Criteria for the Release of Patients
Administered Radioactive Material" is useful (and encouraging). NCRP 37,
"Precautions in the Management of Patients Who Have Received Therapeutic
Amounts of Radionuclides" is still a standard reference. Note that since, at
least, ICRP 26, the question of sexuality has been important. In the short
term, of course, there should be no question that it is verboten. Patients
who've received I-131 for the treatment of thyroid cancer leave the hospital
still excreting therapeutic quantitites of RAM. For that matter, so do
persons treated on an outpatient basis for hyperthyroidism. One would think
that ruling out conception for no less than ten effective 1/2-lives should be
SOP. But as to the dose a partner might receive, there's a large gray area.
Note that the ingestional CEDE for one (1) uCi I-131 is 53 mrem (as per
Federal Guidance Report #11). The ingestion of less than 10 uCi alone, then,
would cause someone to exceed the TEDE of 500 mrem for a year, never mind
external irradiation. That would not, given the large quantities of bodily
fluids exchanged be difficult, certainly in the first few weeks following
discharge. But, where to draw the line? Patients should receive guidance on
this subject, and many places they do not. There also was a good paper in the
J Nucl Med on this, not too long ago; I'll try to retrieve it.

To comment on an earlier string, one would think that there would be cases in
which it'd be appropriate to use the tissue weighting factors for the
estimation of stochastic risk, even if the nominal deterministic limit had
been exceeded. Those would be cases iwhere the dose was in excess of the
recommended/regulatory limit, but not truely near the realm of deterministic
effects. E.g., the ingestion of 40 uCi I-131, where the ALI is 30. Note that
a typical diagnostic dose, for persons with thyroids, is 200 uCi.