title: Lean R value for DXA two-component soft-tissue model: influence of age and tissue or organ type.
abstract: Dual-energy X-ray absorptiometry (DXA) is an important new body composition method that is based on tissue attenuation of two main photon energies. When the two photon energies pass through tissue, attenuation at the lower energy compared with that at the higher energy can expressed as a ratio (R), which is used for tissue component identification. We tested whether: (1) the R value of lean tissue is related to age, and (2) the R value of lean tissue differs between soft tissue locations. Elemental content of various tissues from the literature was used. Results show that lean R values for 40 keV and 70 keV are independent of age and tissue type.
authors.affiliation: Obesity Research Center, St. Luke's/Roosevelt Hospital, Columbia University, College of Physicians and Surgeons, New York, NY, USA.
authors.forename: A
authors.initials: A
authors.lastname: Pietrobelli
authors.forename: D
authors.initials: D
authors.lastname: Gallagher
authors.forename: R
authors.initials: R
authors.lastname: Baumgartner
authors.forename: R
authors.initials: R
authors.lastname: Ross
authors.forename: S B
authors.initials: SB
authors.lastname: Heymsfield
mesh_terms: D015502:Absorptiometry, Photon / Q000379:methods*; D000328:Adult; D000367:Age Factors; D001823:Body Composition; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007668:Kidney / Q000737:chemistry; D008099:Liver / Q000737:chemistry; D008954:Models, Biological; D018482:Muscle, Skeletal / Q000737:chemistry; D009206:Myocardium / Q000737:chemistry; D009928:Organ Specificity; D017785:Photons