X-RAY ANALYSIS
DEXA
Dual Energy X-ray Absorptiometry (DEXA) is a common tool used by clinicians to evaluate fracture risk amongst patients. DEXA measures bone mineral density (BMD), which is a measurement of the bone mineral content (BMC) per unit area (this is due to the fact that DEXA is a projectional technique). BMD has been strongly correlated to bone strength and fracture risk. Since the third dimension of bone is not accounted for, it is not a true volumetric density and therefore there is a dependancy on size (a larger bone with the same volumetric BMC would yield a larger BMD than a smaller bone) (Jergas, et al. 1995).
Jergas, M.A., Breitenseher, M., Glüer, C., Yu, W., Genant, H.K., 1995; Estimates of volumetric bone density from projectional measurements improve the discriminatory capability of dual x-ray absorptiometry, Journal of Bone Mineral Research, 10(7):1101-1110.
For our purposes, BMD and BMC measurements of research animals provide useful information of observable trends in different test groups.