d= 



Radiation Dose in Autoradiography 



f(T)==bTe-^ 

 kBe(«+^)t " 



t(a+A)2 [ 



l_Te-T(-+A)(a+A)-e-T(«+ 



A) 



reps 



131 



(22) 



for T=t: d: 



kB 



t(a+A)2 



forT=oo: d = 



kB 



t(a+A)2 



et(a+A)_(^_|_;^)t_i 



et(a + A) 



reps 



reps 



(23) 



(24) 



Minimum Dose for Long-lived Elements 



For elements with very long half-life or when the time 

 taken up by the experiment is much shorter than the half-life, 

 the radioactive decay during the experiment can be neglected 

 and simpler equations are obtained. 



Applying AjuC per ml. of tracer will result in a concentra- 

 tion of Af(T)jLtC per ml. at time r. Thus to obtain a concen- 

 tration Cq at time t we have to apply: — 



A=;p— - fxC per ml. 

 i(t) 



(25) 



The dose rate at time t will be: — 



d.r.=?ig^k(.) f(.) 



reps per day 



(26) 



Substituting as before, B=61 E^ Cq which will have the 

 values given in expressions (15a) and (15b) we obtain for the 

 dose: — 



B 



f(t) 



k(T) f(T) dr 



reps 



(27) 



o 



The following are solutions of equation (27) for a number 

 of functions for f(T), assuming k to be independent of time. 



