title: Total body composition by dual-photon (153Gd) absorptiometry.
abstract: The lean-fat composition (%FATR) of soft tissue and the mineral mass of the skeleton were determined in vivo using dual-photon (153Gd) absorptiometry (dose under 2 mrem). A rectilinear raster scan was made over the entire body in 18 subjects (14 female, 4 male). Single-photon absorptiometry (125I) measured bone mineral content on the radius. Percentage fat (%FATD) was determined in the same subjects using body density (from underwater weighing with correction for residual lung volume). Lean body mass (LBM) was determined using both %FATR and %FATD. Percentage fat from absorptiometry and from underwater density were correlated (r = 0.87). The deviation of %FATD from %FATR was due to the amount of skeletal mineral as a percentage of the LBM (r = 0.90). Therefore, skeletal variability, even in normal subjects, where mineral ranges only from 4 to 8% of the LBM, essentially precludes use of body density as a composition indicator unless skeletal mass is measured. Anthropometry (fatfolds and weight) predicted %FATR and LBM at least as well as did underwater density. The predictive error of %FATR from fatfolds was 5% while the predictive error in predicting LBM from anthropometry was 2 to 3 kg (3%).
mesh_terms: D000273:Adipose Tissue / Q000033:anatomy & histology; D000328:Adult; D000367:Age Factors; D001823:Body Composition; D001842:Bone and Bones / Q000032:analysis; D005260:Female; D005682:Gadolinium; D006801:Humans; D008297:Male; D008875:Middle Aged; D008903:Minerals / Q000032:analysis; D011868:Radioisotopes; D012737:Sex Factors; D013057:Spectrum Analysis / Q000379:methods
chemical_list: D008903:Minerals; D011868:Radioisotopes; D005682:Gadolinium