Metabolism of Fluorine 18 in Domestic Animals

Abstract

Cyclotron pro-duced radioactive sodium fluoride was used to study: (1) the kinetics of removal of F18 and Na22 from the blood of sheep and cattle, (2) the appearance of ingested F18 in the blood of sheep and cattle, (3) the excretions into the digestive tract of sheep, (4) tissue distribution in sheep, (5) incorporation in the developing hen''s egg, and (6) secretions into the milk of the dairy cow. The initial rate of disappearance of intravenously injected F18 from the blood was found to be 41 and 32% of the dose/minute for the lamb and a mature cow, respectively. The over-all disappearance curve was resolved into 4 components, similar to comparable curves reported for Ca 45. Data from both sheep and cow experiments showed that absorption was rapid, probably occurring from the rumen. Generally, about 1% of the ingested dose represented the peak blood value which occurred at about 2 and 5 hours in the sheep and cow, respectively. The selective localization of F18 in the skeleton appeared to be similar to that of Ca as judged from bone and mandible autoradiograms. It was shown that some of the ingested F18 was deposited in various parts of the hen''s egg and in cow''s milk.