Effect of absorption edge filters on diagnostic x-ray spectra.

The spectra of diagnostic x-ray beams were measured with a germanium semiconductor dectector. With this system it was possible to define the K-alpha-1, K-alpha-2, K-beta-2 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 contst for iodine and barium while substantially reducing radiation dose.