Uptake and distribution of californium-252 chloride administered intraperitoneally, intravenously or intratracheally and the effect of in vivo DTPA chelation on intratracheal instillation in the rat

The first phase of this investigation, comprising of three groups of animals, was designed to study the fate of californium-252 chloride administered intraperitoneally, intravenously or intratracheally. The second phase, which consisted of two groups of animals, was designed to examine the effectiveness of DTPA chelation therapy in accelerating the excretion and preventing the deposition of californium-252 chloride instilled into the lungs of rats. Immediately following the dose administration of 2 uCi of californium-252 chloride which was dissolved in 0.2 ml of 0.9% NaCl at pH 3.5, each rat was placed in a metabolism cage. Each rat in the first group of phase II was given intraperitoneal injection of CaNa3 DTPA (50 mg/kg) and each rat in the second group was given intraperitoneal injections of 0.9% NaCl. Injections of the DTPA or the NaCl sham were initiated immediately after the intratracheal administration of californium-252 chloride and were continued every three days until sacrifice. Following intraperitoneal, intravenous or intratracheal administration, the whole body retention of californium as a function of time was described by a three component exponential equation. For each mode of administration the short term component exhibited a biological half-life of between 5 and 10 hours; the intermediate component between 4 and 6 days; and the long term component between 200 and 300 days. The organ data obtained following intraperitoneal and intravenous administration were indistinguishable. On day one, the liver retained about 9% of the administered dose and the kidneys retained 2.4%. Retention for these organs decreased to about 1% by day 32. The femurs maintained an almost constant level of 4.5% of the injected dose over the 32 days. The lungs, spleen, heart, and testes showed significant retention of californium