title: Dual photon absorptiometry using a gadolinium-153 source applied to measure equine bone mineral content.
abstract: The application of the dual photon absorptiometry (DPA) technique, using gadolinium-153 as the photon source, to evaluate the bone mineral density (BMD) of the third metacarpal bone of horses is presented. The radiation detector was implemented with a NaI(TI) scintillator coupled to a 14 stage photomultiplier. A modular mechanical system allows the position of the prototype to be adjusted in relation to the animal. A moveable carrier makes it possible to scan the third metacarpal with a velocity adjustable between 1 and 12 mm s(-1), in steps of 1 mm s(-1), for a total distance of 250 mm. The prototype was evaluated with a phantom of the third metacarpal bone made of perspex and aluminium, and in vitro with a transverse slice of the third metacarpal bone of a horse. The tests showed that the prototype has an accuracy and precision of, approximately, 10% and 6%, respectively, for a 6 s acquisition time. Preliminary studies carried out in three foals from birth to one year of age indicated that the prototype is well suited to in vivo and in situ analysis of the BMD of the third metacarpal bones of horses, making it possible to evaluate the changes of BMD levels on a monthly basis. Also, results indicated an exponential behaviour of the BMD curve during the first year of life of the studied horses.
authors.affiliation: National Scientific and Technological Development Council, Ministry of Science and Technology, SEPN 509, Bloco A, Sala 204, 70750-901 Brasília, DF, Brazil. amoure@cnpq.br
authors.forename: Alessandro
authors.initials: A
authors.lastname: Moure
authors.forename: Peter
authors.initials: P
authors.lastname: Reichmann
authors.forename: Humberto Remigio
authors.initials: HR
authors.lastname: Gamba
mesh_terms: D015502:Absorptiometry, Photon / Q000295:instrumentation* / Q000379:methods / Q000662:veterinary*; D000375:Aging / Q000502:physiology; D000818:Animals; D015519:Bone Density / Q000502:physiology*; D004867:Equipment Design; D019544:Equipment Failure Analysis / Q000379:methods; D005240:Feasibility Studies; D005682:Gadolinium; D006736:Horses / Q000502:physiology*; D008663:Metacarpus / Q000000981:diagnostic imaging* / Q000502:physiology*; D019047:Phantoms, Imaging; D010865:Pilot Projects; D011868:Radioisotopes; D011877:Radionuclide Imaging; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D011868:Radioisotopes; D005682:Gadolinium