minethe pattern of deposition of fission products. Contact printing on X-ray no-screen film
was found to be the most satisfactory method of preparing the autoradiographs. The discussion
and conclusions presented below summarize the findings reported by Norris et al.'5
The autoradiographof a tibia from a chicken sacrificed at 45 days postdetonation (Fig. 3.2)
indicated a relatively uniform distribution of the activity throughout most of the bone, with the
highest concentration of activity in the area adjacent to the epiphysis. Th‘
rea of high activity
corresponds to an area of dense trabecular bone.
Fig. 3.2——Autoradiograph of Tibia of Chicken Sacrificed 45 Days Postdetonation (ANL).
The tibia and femur of a baby chick, which died spontaneously 47 days postdetonation,
showed the heaviest concentration of radioactive material in the diaphysis (Fig. 3.3). The end
regions of the bone, which were laid down after the animals were removed from the contaminated environment, were relatively lacking in activity. The region of greatest activity was in
the diaphysis, which appeared to be abnormally constricted, possibly because of a decreased
rate of endosteal resorption.
The tibiae from pig 1 sacrificed 45 days postdetonation and from pig 6 sacrificed 58 days
postdetonation each have an area under the growing epiphysis free of activity (Figs. 3.4 and 3.5).
As in the chick described above, this area corresponds to the growth that took place arter the
animals were removed from the area of contamination. The marrow cavity in these tibiae
contained dense trabecular bone along their entire length, a formation not normally found in
mammalian bones. The centers of the diaphysis were abnormally thick, possibly becauseof a
failure of the normal resorptive process. In pig 1 there were also two distinct areas of increased density in the trabecular region, which appear as two lines of radioactivity in the
autoradiograph.
29