• uses
  • The densitometer shown uses an x-ray tube operated at two different voltages to generate a pencil beam, the energy levels of the x-ray photons being a function of the voltage applied. (freepatentsonline.com)
  • Dual-photon absorptiometry is based on the use of radioisotopic sources to provide photons of two different energies whereas the present invention uses an x-ray tube switched between two different voltages in order to generate a collimated beam of two different energies. (freepatentsonline.com)