Performance evaluation of a dual-energy X-ray bone densitometer

摘要: We tested a dual-energy bone densitometer (LUNAR DPX) that uses stable x-ray generator and K-edge filter to achieve the two energy levels. A conventional scintillation detector in pulse-counting mode was used together with gain stabilizer. The normally performs spine femur scans about 6 minutes 3 minutes, respectively, adequate spatial resolution (1.2×1.2mm). Total body take either 10 or 20 minutes. long-term (6 months, n=195) precision of repeat measurement on an 18-cm thick phantom 0.6% at medium speed. Precision errorin vivo 0.6, 0.9 1.5% for (L2-L4) slow, fast speeds, while error 1.2 1.5 2.0%, slow total density 0.5%in vitro andin vivo. response increasing amounts calcium hydroxyapatite linear (r=0.99). accurately indicated (within 1%) actual amount after correction physiological marrow fat. measured area corresponded exactly 0.5%) known annuli radiographic phantoms. There no significant effect tissue thickness mass, area, areal (BMD) between 24cm water. BMD values both femurin correlated highly (r=0.98, SEE=.03 g/cm2) those obtained using conventional153Gd DPA. Similarly, (r=0.96, SEE=.02g/cm2) DPA results.