## Access

You are not currently logged in.

Access your personal account or get JSTOR access through your library or other institution:

## If You Use a Screen Reader

This content is available through Read Online (Free) program, which relies on page scans. Since scans are not currently available to screen readers, please contact JSTOR User Support for access. We'll provide a PDF copy for your screen reader.

# Simulation of Measurements of Uptake of ${}^{123}{\rm I}\text{-Iodide}$ in the Thyroid of Fetal Chimpanzees

J. L. Noteboom, W. A. Hummel, J. Th. M. Jansen, D. W. van Bekkum and J. J. Broerse
Vol. 147, No. 6 (Jun., 1997), pp. 686-690
DOI: 10.2307/3579481
Stable URL: http://www.jstor.org/stable/3579481
Page Count: 5
The quantitative assessment of the uptake of ${}^{123}{\rm I}\text{-iodide}\ ({}^{123}{\rm I}{}^{-})$ in the fetal thyroid in vivo was simulated in phantom measurements. First, the relationship between the depth of the fetal thyroid phantom and the two-peak ratio, the ratio of the counts in the γ-ray and the X-ray energy windows of the registered spectrum, was determined. Subsequently, the attenuation of the γ-ray signal in relationship to the depth of the fetal thyroid phantom was determined. Finally, the relationship between the two-peak ratio and the attenuation of the γ-ray signal was deduced. For a reliable correlation, the signal recorded from the radioactivity surrounding the fetal thyroid phantom has to be subtracted from that obtained with the fetal thyroid phantom present. A correction curve was generated to be applied to the in vivo measurements. It is concluded that with this method determination of uptake of ${}^{123}{\rm I}{}^{-}$ in the fetal thyroid is feasible.