Skip to main page content
Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
, 44 (3), 228-32

Performance Evaluation of a Dual-Energy X-Ray Bone Densitometer

Affiliations

Performance Evaluation of a Dual-Energy X-Ray Bone Densitometer

R Mazess et al. Calcif Tissue Int.

Abstract

We tested a dual-energy bone densitometer (LUNAR DPX) that uses a stable x-ray generator and a K-edge filter to achieve the two energy levels. A conventional scintillation detector in pulse-counting mode was used together with a gain stabilizer. The densitometer normally performs spine and femur scans in about 6 minutes and 3 minutes, respectively, with adequate spatial resolution (1.2 x 1.2 mm). Total body scans take either 10 minutes or 20 minutes. The long-term (6 months, n = 195) precision of repeat measurement on an 18-cm thick spine phantom was 0.6% at the medium speed. Precision error in vivo was about 0.6, 0.9 and 1.5% for spine scans (L2-L4) at slow, medium and fast speeds, while the error was 1.2 and 1.5 to 2.0%, respectively, for femur scans at slow and medium speed. The precision of total body bone density was 0.5% in vitro and in vivo. The response to increasing amounts of calcium hydroxyapatite was linear (r = 0.99). The densitometer accurately indicated (within 1%) the actual amount of hydroxyapatite after correction for physiological amounts of marrow fat. The measured area corresponded exactly (within 0.5%) to that of known annuli and to the radiographic area of spine phantoms. There was no significant effect of tissue thickness on mass, area, or areal density (BMD) between 10 and 24 cm of water. The BMD values for both spine and femur in vivo correlated highly (r = 0.98, SEE = .03 g/cm2) with those obtained using conventional 153Gd DPA. Similarly, total body BMD correlated highly (r = 0.96, SEE = .02 g/cm2) with DPA results.

Similar articles

See all similar articles

Cited by 65 articles

See all "Cited by" articles

References

    1. J Comput Assist Tomogr. 1988 Mar-Apr;12(2):242-58 - PubMed
    1. Med Phys. 1987 Jan-Feb;14 (1):62-9 - PubMed
    1. Am J Roentgenol Radium Ther Nucl Med. 1964 Jan;91:202-10 - PubMed
    1. Med Phys. 1986 May-Jun;13(3):340-3 - PubMed
    1. Radiology. 1985 Jul;156(1):203-6 - PubMed

MeSH terms

LinkOut - more resources

Feedback