Fetal thyroid risk

[HWADE@aol.com]

To: Rad Safe and Rad Sci Groups
From: Wade Patterson
Here's the conclusion from an interesting paper by Ray Lloyd et al.

Lloyd, R. D.; Tripp, D. A.; Kerber, R.A. Limits of fetal thyroid risk from
radioiodine exposure. Health Physics 70:559-562, 1996
Conclusion
Concern for the possible consequences to the fetus of radioiodine
administration to its mother 9 d before conception motivated us to search the
data base for the Utah Fallout study (Stevens et al.)to discover what effects
had been documented among subjects exposed to fallout radioiodine in utero.
Not only was it found that no neoplasia had occurred among this population,
but there were no thyroid effects of any kind in the persons with the highest
thyroid doses (>0.5 Gy). Other, non-neoplastic effects were about as common
among subjects at the lowest dose category (<0.01 Gy) as among those
receiving 0.01-0.2 Gy, indicating that any possible link with radiation
exposure was extremely weak. As an added bonus of this investigation, it was
found that, although the uncertainties were rather large, the fetal thyroid
is probably not much more sensitive to radiation-induced neoplastic change
than is the postnatal thyroid.

Stevens, W.; Thomas, D. C.; Lyon, J.L.; Till, J. E.; Kerber, R. A.; Simon, S.
L.; Lloyd, R. D.; Abd Elghany, N.; Preston-Martin, S. Leukemia in Utah and
radioactive from the Nevada Test Site. JAMA 264:585-591; 1990