Effect of absorption edge filters on diagnostic x-ray spectra

The spectra of diagnostic x-ray beams were measured with a germanium semiconductor detector. With this system it was possible to define the k/sub α1/, k/sub α2/, k/sub β1/, and k/sub β2/ characteristic peaks of the tungsten target. The effects of various filters on the beam using characteristic absorption edges to create a ''bandpass'' effect were studied. Gadolinium filtration of the diagnostic beam used for contrast studies selectively removed both higher energy photons (greater than 50 keV) and lower energy photons (less than 33 keV) thus enhancing contrast for iodine and barium while substantially reducing radiation dose. (U.S.)