Patent ID: 7479639
Filing Date: 2009-01-20
Classification: G01T

Abstract:
1. An apparatus for determining energy windows in an imaging system having a single photon counting mode, the apparatus comprising: a pixilated radiation detector having an array of detector elements, each of said detector elements coupled to a respective electronic channel, wherein detection of a photon at one of said detector elements produces a signal carried by the respective electronic channel; a multi-channel analyzer to measure the signals carried by said channels and to generate two respective spectra for each of said detector elements, said spectra corresponding to two respective energy levels of photons in radiation flux impinging on the detector; a correction unit to correct the signals for each of said detector elements by applying an electrical offset correction derived from the two respective spectra, and to determine a corrected spectrum of radiation flux for each of said detector elements, based on respective corrected signals; and an energy window determiner to determine, for each of said detector elements, a peak channel of the respective corrected spectrum, said peak channel having a highest number of counts, and to determine an energy window in the respective corrected spectrum, said energy window having a width equal to a desired fraction of the width of said peak channel.