RESUMEN
A technique to measure total body calcium using the 40Ca(n, alpha)37 Ar reaction has been developed. The technique is based on collecting 37Ar exhaled in the breath following a 10 mrad uniform total body irradiation by 14 MeV neutrons. The 37Ar in the exhaled breath is extracted by selective absorption and its radioactivity is measured inside a low-background proportional detector. The facilities developed include an activation facility providing a +/-2.7% activation uniformity, a closed circuit rebreathing and gas collection system, and a gas purification and counting system. The technique provides a precision of +/-2.4% as determined by repetitive measurements of human volunteers and has an accuracy for determination of total body calcium in grams of +/-5%.
Asunto(s)
Calcio/análisis , Argón/análisis , Pruebas Respiratorias , Humanos , Métodos , Análisis de Activación de Neutrones , Dosis de Radiación , Radioquímica , Radioisótopos/análisisRESUMEN
Measurements of exhaled Ar-37 produced by total-body neutron irradiation of Ca-40, were used to determine total-body calcium in ten human subjects. There was a good correlation between the Ar-37 yield and total-body calcium determined by measurement of Ca-49.
Asunto(s)
Composición Corporal , Calcio/análisis , Adulto , Anciano , Argón/análisis , Humanos , Persona de Mediana Edad , Análisis de Activación de Neutrones , Radioisótopos/análisis , RespiraciónRESUMEN
Measurements of exhaled 37-Ar produced by total-body neutron irradiation of 40-Ca were used to determine total-body calcium in 16 human subjects. There was a good correlation between body calcium using the 30-min postirradiation breath sample of 37-Ar and body calcium determined by measurement of 49-Ca.
