quality:correction, information:filtering
Physics

One type of DXA scanner uses a cerium filter with a tube voltage of 80 kV, resulting in effective photon energies of about 40 and 70 keV. Another type of DXA scanner uses a samarium filter with a tube voltage of 100 kV, which produces effective energies of 47 and 80 keV. Also, the tube voltage can be continuously switched between a low (for example 70 kV) and high (for example 140 kV) value in synchronism with thefrequency of the electrical mains, resulting in effective energies alternating between 45 and 100 keV.