fi tes Y t Urinary radioiodine excreiion at 15 days. J day “i day -1 K X10 3 L day -1 X10 0.2 dI, . —_ at % of Le ¢/ day 3.7 4.85 7.2 0.050 3.7 4.85 13.8 0.066 3.7 17.15 7.2 0.16 3.7 17.15 13.8 0.21 —_—— On the basis of these calculations, the normal range of urinary radio- iodine’ excretion at 15 days was estimated to be C.05 to 0.2% of the peak thyroid content. The problem outlined above is a practical application of an analytical study on the uptake and cxcretion of iodine in man which will be described at : Neen award ww © jae -F on C1 more fully in a UCKL report entitled, ''The Dynamics of Iodine in Man."