title: In vivo measurement of total body chlorine using the 8.57 MeV prompt de-excitation following thermal neutron capture.
abstract: Prompt gamma neutron activation analysis with 238Pu/Be sources is used to measure total body chlorine (TBCl) in vivo following the reaction 35Cl(n, gamma)36Cl. The chlorine de-excitation at 8.57 MeV is used for calibration of the system for TBCl. Body hydrogen is used as an internal standard and TBCl is derived from the gamma-ray counts ratio of chlorine to hydrogen. The precision of the method, determined from replicate scans of a Bush-type phantom, is 4.9% (CV). To assess accuracy an anthropomorphic phantom consisting of minced meat was constructed. Replicate scans of this phantom yielded a mean total chlorine which was not significantly different from the chemical analysis value. The subject dose equivalent for the activation measurement is less than 0.3 mSv. Mean TBCl values for 63 male and 107 female healthy volunteers were in broad agreement with predicted amounts based on multiple regression equations developed at other centres from measurements using the delayed gamma approach. Good agreement was observed in 76 volunteers between total body water (TBW) measured by tritium dilution, after correction for non-aqueous hydrogen exchange, and TBW derived from the sum of extracellular water and intracellular water as measured by TBCl and total body potassium (TBK), respectively.
authors.affiliation: University Department of Surgery, Auckland Hospital, New Zealand.
authors.forename: S
authors.initials: S
authors.lastname: Mitra
authors.forename: L D
authors.initials: LD
authors.lastname: Plank
authors.forename: G S
authors.initials: GS
authors.lastname: Knight
authors.forename: G L
authors.initials: GL
authors.lastname: Hill
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001823:Body Composition; D002138:Calibration; D002713:Chlorine / Q000032:analysis*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008961:Models, Structural; D009501:Neutron Activation Analysis / Q000379:methods
chemical_list: D002713:Chlorine