The whole body retention at any time t-t of the fraction of initial radioactivity inputed at time Tt is Exe a tKi dC t-t) hu Thus, the instantaneous activity at time t-T that remains following input during dt is 0 g-(KEtA)T EyeAtRid (tT) ag A£,P 1 “1 . It follows that the instantaneous activity at time t-T that remains following input during T is J T } AF Pe ~(Kg+h)T 1 r.X.e C0 +K3) (t-T) i*i dt. The solution of the integral yields a general expression that depends on the user defining t. For example, if t is the fixed uptake interval, T, plus an additional fixed post uptake interval, @, then the body burden at T + 9% is given by AP°£) LZixg Ce ~(AtKe)T Ese -—(AtK:)T mye --(A +K3) @ * KR, -K& As previously stated, Eq. (2) appifed at Rongelap and Utirik, it was for the situation that variable time t was the uptake interval. Additionally, persons who returned to the atolls in June 1954 and June 1957 did so with an initial body burden, q°. The behavior of this contribution to body burden, q, was embodied in the q° term of Eq. (2). A similar model was used to relate Mt: