DENSITOMETRIC MANIFESTATIONS IN AGE-RELATED BONE LOSS

MAUTALEN CARLOS A.; BEATRIZ OLIVERI *

THE AGING SKELETON

C Rosen - J Glowacki and J Bilezkian, Academic Press

Lugar: New York; Año: 1999; p. 263 - 276

Introduction:             The modern development of bone densitometry as a practical, clinical toll began at the University of Wisconsin, in the 1970´s. The initial technique –single photon absorptiometry (SPA)- used a low-energy radionuclide source (Ionide-125 at 28 keV or Americium-241 at 60 keV) was detected with a highly collimated scintillation detector coupled  to single-channel analyzer. A narrow beam was passed across the area of interest, usually the distal third of radius. Only peripheral sites could be measured because a constant tissue thickness had to be maintained using water bath. Measurements required 5 to 10 min with a precision error of approximately 2 %. In the 1980´s, the SPA approach was improved by dual-photon absorptiometry (DPA). The new technique used a dual-energy radioisotope (Gadolinium-153 utilizing radiation at two different energies: 44- and 100keV). DPA allowed measurement of de axial skeleton, spine and femur, as well as the total body.