rete A eae eeeTate en Sm a ir ed 38 INTERNAL DEPOSITION GF RaseueUCLIDES Pictuage 3.2—Amtoradiograph of tibia of chicken sacrificed 45 days post: dctonation (ANL). Marrow cavity tn this tibia contaimed dense trabecular bone along its entire length, a formation not normally found in manimalian bones. There are also two distinct areas of increased density in the trabecular region, which appear as two lines of radioactivity in the autoradiograph. The center of the diaphysis was abnormally thick, possibly because of a failure of the normal resorptive process. No other evidence of a double line of radio- active deposit appeared in the animals studied, © except possibly in a sow sacrificed 38 days post exposure (Fig. 5.5). Here a faint deposit of activity in the trabecular bone is noted, separate from the higher level in the epiphysis. Looney (4) has shown that a typical osseous tissue in trabecular space is a characteristic lustopathologiceal finding following radioactive

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