Jl. Noteboom et al., SIMULATION OF MEASUREMENTS OF UPTAKE OF I-123 IODIDE IN THE THYROID OF FETAL CHIMPANZEES, Radiation research, 147(6), 1997, pp. 686-690
The quantitative assessment of the uptake of I-123-iodide (I-123(-)) i
n the fetal thyroid in vivo was simulated in phantom measurements. Fir
st, the relationship between the depth of the fetal thyroid phantom an
d the two-peak ratio, the ratio of the counts in the gamma-ray and the
X-ray energy windows of the registered spectrum, was determined. Subs
equently, the attenuation of the gamma-ray signal in relationship to t
he depth of the fetal thyroid phantom was determined, Finally, the rel
ationship between the two-peak ratio and the attenuation of the gamma-
ray signal was deduced. For a reliable correlation, the signal recorde
d from the radioactivity surrounding the fetal thyroid phantom has to
be subtracted from that obtained with the fetal thyroid phantom presen
t. A correction curve was generated to be applied to the in vivo measu
rements. It is concluded that with this method determination of uptake
of I-123(-) in the fetal thyroid is feasible. (C) 1997 by Radiation R
esearch Society.