title: A system for measuring total body calcium in man using the 40Ca(n, alpha)37 Ar reaction.
abstract: 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%.
mesh_terms: D001128:Argon / Q000032:analysis; D001944:Breath Tests; D002118:Calcium / Q000032:analysis*; D006801:Humans; D008722:Methods; D009501:Neutron Activation Analysis; D011829:Radiation Dosage; D011854:Radiochemistry; D011868:Radioisotopes / Q000032:analysis
chemical_list: D011868:Radioisotopes; D001128:Argon; D002118:Calcium