The whole body retention at any time t-t of the fraction of initial radioactivity inputed at time Tt is Eye Atki (et) i*i Thus, the instantaneous activity at time t-T that remains following input during a4 dt is Af P 9 e -(Kg+h dt bye 7RINE gy wi1 It follows that the instantaneous activity at time t-T that remains following input during T is T J A£,Pee 2 ~(Kpth dt ° L.x.e i*1 —(A+Ky) Ct-1) . 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 + @ is given by AP°£) Zixg Ce -(\+Kg)T -e ~Q4K{)T, e ~—(AtK;) 6 K. - K, As previously stated, Eq. (2) applied 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