Cross-calibration of DXA equipment: Upgrading from a hologic QDR 1000/W to a QDR 2000

摘要: In this study, the cross-calibration of a fan beam DXA system (Hologic QDR-2000) to pencil scanner from same manufacturer QDR-1000/W) is described. The scanners were calibrated by using anthropomorphic spine phantom at installation. To verify consistent machine calibration, group 69 female subjects, aged 46–75, had anteroposterior (AP) and proximal femur scans on QDR-1000/W followed array sites QDR-2000 during visit. Many subjects bilateral examinations for total 123 hip scans. Pencil area, bone mineral content (BMC), density (BMD) compared with values obtained QDR-1000/W, linear regression equations derived relating two instruments. At spine, no differences found between BMD values. A slight difference modes was detected but not deemed clinically significant. Linear models AP measurements showed correlation coefficients greater than 0.99, slopes 1.00, intercepts equivalent zero, small root mean square errors. Comparisons equivalency femoral neck trochanter regions machines in mode, increases BMC other both mode. Correlation 0.97–0.99 all measurement except Ward's. Regression 1.00–1.04, significantly different zero residual As enough that they clinical significance. However, longitudinal drug trials requiring highly precise determination spinal changes, these may be important.