36 RESULTS AND DISCUSSION Barium-133 emits two strong gamma rays, one at 81 keV and one at 360 keV, as well as other less in- tense gammarays. It was of interest to note that the shape of the spectrum as recorded by this particular Nal (Tl) crystal, remained unchanged throughout the TABLE 10. Excretion Data Percent injected dose Sample 1BBa Day Percent injected dose *Ca 576 A22B A22C A22D A22D A22B Feces 1 2 3. 4 5 6 7 — ~~ 3.17 1.28 11.16 — _— — — — 0.439 0.298 0.118 _— 0.386 8.599 7.191 8.708 2.495 2.560 2.666, 0.541 2.289 5.315 10.599 3.552 3.429 1.158 0.883 2.868 6.065 14.174 5.430 11.891) 2.969 0.609 10.060 12.672 12.930 10.067 4,027 2.020 Urine 1 2 3 4 5 6 7 — — 2.78 0.85 1.06 — — — — — 0.270 0.877 0.162 — 8.406 3.785 2.742 1.389 1.540; 0.806 1.030 16.374 4.1380; 4.466) 1.842 2.3802] 2,026 0.876 0.816 0.045 0.377 —_ 1.781 0.285 0.327 1.110 1.461 0.657 0.624 0.555 0.619 0.284 1 2 3 4 5 6 7 _— ne — — 1.62 0.79 0,72 — 0.046 2.27 2.62 6.27 1.62 | | 3.18 2.59 0.03 0.55 1.19 5.75 1.54 1.69 1.32 Feces / urine 14 51) —_ TABLE 11. Distal metaphysis Distal epiphysis Distal metaphysis plus distal epiphysis Tibia Humerus Radius Ulna Lumbarvertebra Total femur an original burden measurement immediately aft: jection and before any excretion has taken pl: valid as the 100% point, and the spectrum thu tamed may be compareddirectly to any later sp: even though the location of the isotope within th is not the sameat later times. Figure 32 indicates that the retention of ***] these animals is not exactly described by a |] function.“”) It is clear that the plot of retentio time does not yield a straight line on log-log co nates; this is particularly true for the older dogs. It should be noted that the plasma concentrati 183Ba shown in Figure 32 has been expressed it same units as the retention. This type of plot s: the relationship between the specific activity ol plasma and that of the skeleton. A straight line can be drawn through the plasma centration points from day 2 to day 7 or day 14 o1 data from three of the animals. Dog A22D, how: indicates a definite departure from a straight line ing this time interval. The values for the interva. tween 1000 and 1900 days (See Dogs A22B and indicate that the plasma concentration did not tinue to fall as rapidly during the entire exposure riod. The significant point is that by 1000 days : the isotope administration the plasma specific acti is a factor of fifty below that of the skeleton. Thes! of these blood curves on the log-log plot is typicz 156 A22D A22C A22B {1508 days from (7 days from (7 days from (7 days from 0.040 0.025 0.035 0.089 0.043 0.070 0.154 0,155 0.155 0.201 0.150 0.166 _ — 0.103 0.042 0.057 0.066 0.075 0.095 0.075 0.146 0.149 0.212 0.181 _ 0.079 0.086 0.152 0.081 0.086 0.086 0.106 0.091 injection) Mid-shaft 0.55 6.89 19.29 20.72 18.14 6.51 7.11 sorption and scattering of the gammaradiation w sentially the same after the isotope was dep: within the bone as it was when the isotope was © the blood. Thus, in this ease, the technique of reco 1#Ba ConcENTRATIONS IN Various BoNEsS (PERCENT INJECTED Doss PER GRam ASH) 576 Femur Proximal epiphysis Proximal metaphysis Proximal epiphysis plus proximal metaphysis 1.08 63.738 16.09 _— 3.05 41.7 9.08 period of observation, namely from minutes to after injection. This indicates that the effectiv 0.018 injection) 0.026 0.039 0.032 0,030 0.031 0.035 0.047 0.072 0.042 0.044 0.046 0.039 0.033 0.035 0.095 0.068 injection) 0.153 0.070 0.126 0.057 0.069 0.094 0.138 injection) 0.134 0.116 0.152 (3113 days fro injection) — 0.052 0.083 gd