= 114 TABLE 54. Summary or DEFINITIONS USED IN NorRMALIZATION PRocEDURE FOR ?2Th anp 2@Ra Quantity | 22h Activities in injection material | | 28h Bo Co A = ady B C 7 f= “Ra 1 22TH | | AL Aa | _ | Steady state activity ratio at f= Deeay constants 28Ra Ag at time of injection Activities in tissue sample at time ¢ after injection | | Bateman coefficients for growth and decay of ?8Ra (see Figure 88} Growth from *?Th of type II #*Ra Bateman coefficients for growth and decayof #°Th (see Figure 88) Growth from ??Th of type HI *8Th b ’ ods C1 | e = Ne hyd —e ? Az hat 2 bs =e Growth from 74Ra of eo _ et dye eu —e™ Ag —* Aa — de type II ?8%Th ‘ ~ (Xe — &) _ ™sTh: BERa Decayof type I 2*%Th —Ayt (Ae — &) 2 et? —e 3° ‘Cy = | , Decay of type | C3 = ewhye SO AB — ha ‘) This is taken to mean the material actually administered, which is not necessarily the same as the material in the an or even the material in the syringe. 100L 7 ' TTT tT] r T CAS _ ZF B WW oO te x & 0 o - fe Z L a LL. a a * ae BY, £& = , | % A a o x K SS Qe Oe o w w oO @\¥ 5,> on we “se 4,a s. a ¥ ow< oy 4 eR,2 e gE = 4 = e z2 1 ; ooF Ss Tees 4 % 2, - ee o | 10 piri! ofr pei! i00 1000 DAYS to Nt [0,000 ; Fic, 88.--Bateman coefficients for the growth and decayof ?*Ra and ?8Th same proportionsaf,f2/fife amongthe tissues as do 28Th atoms of type III, and with a whole-bodyretention of fifz. Type I 28Th atoms, however, must be treated somewhatdifferently since they do not growzn vivo from 8Ra and, therefore, cannot depend on theratio fi/fi . Thus it cannot be expected that type I “*Th atoms will behave in the same manneras the atomsof types IT and IJ; rather they bear an analogy with type I *8Ra atoms. In the case of #8Ra, one is interested in the tion: what fraction of the atoms in the injectior terial is carried by the Thorotrast particles? For 1 8Th, exactly the same question arises. Therefor analogy with ?8Ra it will be assumed that the v body retention of type I ?8Th atomsis fz and th: retained atomsare distributed among the tissues | time of measurement in the proportions af2/fe.