Material discriminated x-ray CT by using conventional microfocus x-ray tube and cdte imager

Abstract

Material discriminated X-ray CT system has been constructed by using conventional micro-focused X-ray tube (small white X-ray source) and photon counting type CdTe X-ray imager with energy-band discriminate function. We have already reported material identify X-ray CT using K-shell edge data. In this report the principle of material discrimination was adapted the separation of electron-density and atomic number from attenuation coefficient mapping in X-ray CT reconstructed image in dual energy X-ray CT method. The dual energy X-ray method was obtained good electron-density mappings by using two monochrome X-ray source, however, it is difficult for very large-scale equipment such as an accelerator to be necessary and to apply this system to homeland security field at the airport and so on. The measurement sample was prepared as three kinds material rods (aluminum(Al), titanium(Ti) ,iron(Fe) of 6mm-diameter). We could observed material discriminated X-ray CT reconstructed image, however, the discrimination properties were not good than two monochrome X-ray CT method. This results was could be explained because X-ray scattering, beam-hardening and so on based on white X-ray source, which could not observe in two monochrome X-ray CT method. However, since our developed CdTe imager can be detect five energy-bands at the same time, we can use multi-band analysis to decrease the least square error margin. We will be able to obtain more high separation in atomic number mapping in X-ray CT reconstructed image by using this system.