V3 is, there seems to be a higher proportion of cancer per total neoplasms than with the radioicdine studies, but I'll admit there isn't always comparability and many of you could then say, ‘But we don't know how many of these who are still walking around may have adenomas."' We know that in adult populations there is a high incidence of thyroid _ adenomas; in fact, in those of you who are over 50 years old, if we removed your thyroid [if it isn't already removed) we would probably find adenomas in half of you. A study was done several years ago in which it was shown that half of the people over 50 had thyroid adenomas and most of them didn't know it and seemed none the worse for them. T_..e moral of the story is if you're going to have a neoplasm, choose the thyroid. FREMONT-SMITH: Were any primates used in the experimental animals, any monkeys which might be closer to man? BUSTAD: The only studies in the sub-human primates that I'm familiar with are those by Pickering (Reference 30}, and he was concerned mainly with the uptake in the very young—the fetal thyroid. There have been no long-term studies with radioiodine in primates to my knowledge. i think that most of the data that I've reviewed—and I think Lhave reviewed most of it in this field—certainly indicated to me the species that have been worked on..... FREMONT-SMITH: BUSTAC: Well, no. But they're all lower species? We've alsolocked at human cases where there was radioiodine given. FREMONT-SMITH: Okay. BUSTAD: The effect is similar. It will take an acute dose of 30, 000 to 50, 000 rads to ablate the thyrcid of sheep. Dr. Goolden (Reference 31) in England, looking at a lotof human cases says it will take a comparable dose for a human adult. There's one exception to this that some of you may bring up. and that is the work of Dr. John Garner now at Colorado State Univerisity (Reference 32) who says , that cattle thyroids are unusually resistant and may take over 100, 000 rads. In all of these cases a lower dose will cause hypothyroidism if you wait long enough. WARREN: The jack rabbit is susceptible, too. 7 ath SESSION fil