Author(s): Graham Hart

Hospital: YourRPA

Reference: RAD Magazine, 46, 544, 31-32

Excerpt: 

Dual-energy x-ray absorptiometry (DXA or DEXA) has been the standard method for measuring or monitoring bone mineral density for many years, used principally for the assessment of osteoporosis and hence the risk of bone fracture. It is also now increasingly being used for the assessment of body composition.

The concept behind DXA is to make transmission measurements through a patient using x-ray beams of two different energies or spectra. Typical energies are in the range 70-75kVp and 130-140kVp. Either two beams of separate energies are used, or now more commonly two separate energy measurements are made from a single x-ray beam.