Radium Isotope Accumulation in Animal Thyroids

Abstract

Uranium and thorium daughters are ten times more concentrated in thyroids from some bovine animals than in the teeth of the same animals. These radioactive isotopes are believed to be from natural sources, but their resulting annual dosage of thyroid radiation has exceeded that from iodine-131 fallout.

Microscopic Distribution of Americium-241 in the Beagle Thyroid Gland

“…Deposition of 210Po in rat thyroids, at relatively short postinjection intervals, was shown by TRACHEV. (14) The radioactivity from zz6Ra in the thyroids of cattle, raised in Columbia, was found by MIDDLESWORTH et uZ., (15) to be 4-10 times greater than the tooth factor. I n the above instances, where autoradiography was done, the dog and rat studies, at least part of the burden was in the connective tissue and very little, if any, was found in the colloid.…”

Concentrated Sources of Alpha Particles within Thyroid Glands

“…R ADIUM and thorium have been shown to concentrate in the thyroids of occasional cattle and the concentration in such thyroid glands was 10-20 times greater than in the teeth of the same animals (1). During the past 2 yr we have prepared radioautographs of 13 bovine thyroids which were found to contain gamma spectra of radium and/or thorium.…”