THYROID METABOLISM IN CHILDREN AND ADULTS USING VERY SMALL (NANOCURIE) DOSES OF IODINEsup125sup 125 AND IODINEsup13sup 13sup1sup 1

A new technique for measuring the radioiodine content of the human thyroid in vivo with nanocurie amounts of I/sup 131/ and I/sup 125/ is described. The technique gives a measure of the thickness of neck tissue over the thyroid; values of 0.4 and 2.0 cm have been found in the subjects studied thus far. Results on 6 normal adults show uptake at 7 days after oral ingestion varies between 15 and 29%, with biological half times between 27 days and infinity. Results on 8 normal children (ages 4 to 10 yr) show little or no difference from adults as far as the data extend (15 days post oral ingestion). Uptakes vary between 9.5 and 27%, and biological half times are long compared to the 8-day physical haif life. (auth