Salivary Secretion of Caesium-131

Abstract

IN previous investigations it has been shown that potassium-42 and rubidium-86 are rapidly cleared from the blood and secreted into the saliva in identical fashion^1,2. This has led to the development of techniques for the determination of exchangeable potassium with ⁴²K or ⁸⁶Rb, using saliva rather than urine, since urinary excretion of these two isotopes differs². In an investigation of the applicability of the recently reactor-produced caesium-131 (physical half-life, 9.5 days; 29.4-keV X-ray) as a substitute for the short-lived gamma-emitters ⁴²K (physical half-life, 12 h) and the relatively long lived ⁸⁶Rb (physical half-life, 18.6 days) differences in the salivary excretion of ¹³¹Cs and ⁴²K or ⁸⁶Rb were noted.