Apparatus, method and system for determining energy windows in medical-imaging systems

A method for determining energy windows in an imaging system having a single photon counting mode, the method comprising:

• measuring detection signals carried on electronic channels that are respectively coupled to an array of detector elements of a pixilated detector, wherein detection of a photon at one of said detector elements produces a signal carried by the respective electronic channel;
• generating two respective spectra for each of said detector elements, based on the signals produced for said detector elements and carried on said channels, said two respective spectra corresponding to two respective energy levels of photons in radiation flux impinging on the detector;
• deriving a respective electrical offset for each of said detector elements, based on the two respective spectra, and correcting the signals produced for each of said detector elements by applying said respective electrical offset;
• constructing a corrected spectrum of radiation flux for each of said detector elements, based on respective corrected signals;
• determining for each of the detector elements a peak channel of the respective corrected spectrum, said peak channel having a maximum of counts;
• and
• determining for each of the detector elements 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.

An imaging system having a single photon counting mode, the system 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;
• 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;
• and
• a display to display a reconstructed image having pixels corresponding to said array of detector elements, wherein each pixel of the reconstructed image is based a total number of counts within the energy window determined for the respective corrected spectrum of the corresponding detector element.