Development of Dual-Energy X-ray CT using Synchrotron Radiation

Monochromatic x-ray CT at two different energies provides information about electron density without ambiguity due to the beam hardening effect. This information makes the treatment planning for heavy-ion radiotherapy more precise. We have started a feasibility study on the dual-energy x-ray CT by using synchrotron radiation. We developed a linear scanning CT system(1D-CT) in order to evaluate what precision in the measurement was achieved. Comparison fo measured electron densities with the theoretical values proved that these values were in afreement in 0.9 % on average. We haave developed a 2D-CT system with a two-dimensional scintillator array to take images in a short time. At present, it has been proved that the electron density is measured in the precision of about 1 %. Effectove atomic numbers are obtained as well from the dual-energy x-ray CT. They present a different feature of an object, and the contrasts in the images differ from that in a conventional CT image. The feature of the images may help distinguish more clearly tissues or organs with aid of difference contrast from the conventional CT images.International Symposium on Portable Synchrotron Light Sources and Advanced Application