title: Human metabolism of orally administered radioactive cobalt chloride.
abstract: This study investigated the human gastrointestinal uptake (f1) and subsequent whole-body retention of orally administered inorganic radioactive cobalt. Of eight adult volunteers aged between 24 and 68 years, seven were given solutions of (57)Co (T1/2 = 272 d) containing a stable cobalt carrier, and six were given carrier-free (58)Co (T1/2 = 71 d). The administered activities ranged between 25 and 103 kBq. The observed mean f1, based on 6 days accumulated urinary excretion sampling and whole-body counting, was 0.028 ± 0.0048 for carrier-free (58)Co, and 0.016 ± 0.0021 for carrier-associated (57)Co. These values were in reasonable agreement with values reported from previous studies involving a single intake of inorganic cobalt. The time pattern of the total retention (including residual cobalt in the GI tract) included a short-term component with a biological half-time of 0.71 ± 0.03 d (average ± 1 standard error of the mean for the two nuclides), an intermediate component with a mean half-time of 32 ± 8.5 d, and a long-term component (observed in two volunteers) with half-times ranging from 80 to 720 d for the two isotopes. From the present data we conclude that for the short-lived (57)Co and (58)Co, more than 95% of the internal absorbed dose was delivered within 7 days following oral intake, with a high individual variation influenced by the transit time of the unabsorbed cobalt through the gastro-intestinal tract.
authors: Radiation Physics, Skåne University Hospital, 221 85 Lund, Sweden. Electronic address: hanna.holstein@med.lu.se.
authors: H
authors: H
authors: Holstein
authors: Barsebäck Kraft AB, Box 524, 246 25 Löddeköpinge, Sweden. Electronic address: ylva.ranebo@vattenfall.com.
authors: Y
authors: Y
authors: Ranebo
authors: Medical Radiation Physics, Department of Clinical Sciences in Malmö, Lund University, Skåne University Hospital, SE-205 02 Malmö, Sweden. Electronic address: christopher.raaf@med.lu.se.
authors: C L
authors: CL
authors: Rääf
mesh_terms: D000284:Administration, Oral; D000328:Adult; D000368:Aged; D003035:Cobalt / Q000493:pharmacokinetics*; D003036:Cobalt Isotopes / Q000493:pharmacokinetics; D003037:Cobalt Radioisotopes / Q000493:pharmacokinetics*; D005260:Female; D065569:Gastrointestinal Absorption; D006801:Humans; D008297:Male; D014018:Tissue Distribution; D055815:Young Adult
chemical_list: D003036:Cobalt Isotopes; D003037:Cobalt Radioisotopes; D003035:Cobalt; C018021:cobaltous chloride
keywords: Biokinetic study; Biological half-time; Radioactive cobalt