Contrast Enhancement in Mammography Imaging Including K Edge Filtering

A general X-ray tube has two electrodes, the cathode and the anode, with a high voltage applied between them. Electrons are generated at the cathode. After the electrons are emitted from the cathode they are accelerated by the high voltage toward the anode (positive) electrode. The high speed electrons hitting the anode material then generate invisible radiation i.e. X-rays. The energy spectrum of the output X-rays is dependent on the anode-cathode voltage difference and on the material of the anode and is measured in electronvolts. The energy spectrum is a so called Brehmstrahlung radiation meaning that it is continuous over a wide range of energies and has more photons emitted at the lowest energies. The photon flux decreases to zero at the anode-cathode voltage difference level.