Identification of a material with a photon counting x-ray CT system

Modern x-ray CT systems measure the total energy of all photons incident to detectors, and thus it is very difficult to identify a medium with an x-ray CT image. We proposed a new method to identify a medium with an x-ray CT system, in which we used a detector that could measure photons with several energy windows. Our method identifies an object with a set of linear attenuation coefficients of the object reconstructed as an image for each energy window. As for the reference data in this identification, we calculated a set of linear attenuation coefficients for an individual medium beforehand, and compared this reference dataset with that measured with the photon counting x-ray CT. To evaluate the validity of our proposed method, we conducted some simulations and experiments with several typical materials. It was found to be possible to identify the materials with this kind of photon counting x-ray CT system.