title: Dual-photon absorptiometry: comparison of bone mineral and soft tissue mass measurements in vivo with established methods.
abstract: This study extended initial observations that indicated the potential of dualphoton absorptiometry (DPA) to measure total-body bone mineral (TBBM) and fat in vivo. DPA-derived TBBM and fat were compared with established methods in 13 subjects (aged 24-94 y) who underwent measurement of body density (Db), total-body water (TBW), potassium (TBK), calcium (TBCa, delayed-gamma neutron activation), and nitrogen (prompt-gamma neutron activation). TBBM was highly correlated with TBCa (r = 0.95, p less than 0.001) and the slope of TBCa vs TBBM (0.34) was similar to Ca content of ashed skeleton (0.34-0.38). DPA-measured fat (means +/- SD, 16.7 +/- 4.9 kg) correlated significantly (r = 0.79-0.94; p less than 0.01-0.001) with fat established by Db (16.3 +/- 5.4 kg), TBW (16.0 +/- 4.3 kg), TBK (17.7 +/- 4.6 kg), combined TBW-neutron activation (17.6 +/- 5.9 kg), and means of all four methods (16.9 +/- 4.8 kg). DPA thus offers a new opportunity to study human skeleton in vivo and to quantify fat by a method independent from the classical assumption that bone represents a fixed fraction of fat-free body mass.
authors.affiliation: Department of Medicine, St Luke's-Roosevelt Hospital Center, Columbia University School of Medicine, New York, NY.
authors.forename: S B
authors.initials: SB
authors.lastname: Heymsfield
authors.forename: J
authors.initials: J
authors.lastname: Wang
authors.forename: S
authors.initials: S
authors.lastname: Heshka
authors.forename: J J
authors.initials: JJ
authors.lastname: Kehayias
authors.forename: R N
authors.initials: RN
authors.lastname: Pierson
mesh_terms: D000273:Adipose Tissue; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001823:Body Composition; D001834:Body Water / Q000032:analysis; D001835:Body Weight; D001842:Bone and Bones / Q000032:analysis*; D002118:Calcium / Q000032:analysis; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008903:Minerals / Q000032:analysis*; D009584:Nitrogen / Q000032:analysis; D011188:Potassium / Q000032:analysis; D011877:Radionuclide Imaging
chemical_list: D008903:Minerals; D009584:Nitrogen; D011188:Potassium; D002118:Calcium