Kidney Disease in Beagles Injected with Polonium-210

An unusually high incidence of kidney disease (tubular degeneration and necrosis with fibrous replacement) was observed among 24 beagles injected at about 5 years of age with 116 or$329\ {\rm kBq}\ {}^{226}{\rm Ra}\ {\rm kg}^{-1}$but not among an additional 10 beagles given about$329\ {\rm kBq}\ {}^{226}{\rm Ra}\ {\rm kg}^{-1}$. This226Ra solution also contained^{210}{\rm Pb},\ {}^{210}{\rm Bi}$, and210Po. To determine whether the kidney disease was related to the radiation from226Ra and its short-lived progeny or to the α radiation from210Po, 2 beagles about 7 years of age were injected with 451 kBq^{226}{\rm Ra}\ {\rm kg}^{-1}$from which the^{210}{\rm Pb},\ {}^{210}{\rm Bi}$, and210Po had been removed, and 4 other beagles about 7 years of age were injected with$122\ {\rm kBq}\ {\rm kg}^{-1}$of210Po citrate. Measurements of polonium retention in the kidneys of these dogs and of bismuth retention in the kidneys of 4 additional beagles given^{210}{\rm Bi}$citrate enabled us to model the retnetion of these emitters in the dog kidney and to estimate the kidney dose from the α radiation of210Po following injection of either^{226}{\rm Ra}+{}^{210}{\rm Bi}+{}^{210}{\rm Po}$or210Po only. Autoradiography revealed that almost equal concentrations of210Po were in the tubular epithelium and/or its basement membrane and in the glomeruli, but very little of the^{210}{\rm Bi}$deposited in kidney tissue was present in the glomeruli. Radiation damage to the kidneys similar to that observed previously in beagles given226Ra solutions that also contained^{210}{\rm Bi}$and210Po was seen among the beagles given210Po but not in the dogs given purified226Ra. The analysis of these data indicated that the relatively high incidence of kidney disease among the mature beagles injected with226Ra and its accompanying^{210}{\rm Bi}$and210Po resulted from α irradiation of the kidneys by the substantial amount of210Po that was in the injection solution.