Dual-Energy X-Ray CT by Compton Scattering Hard X-Ray Source

We are developing a compact Compton scattering hard X-ray source by the X-band linac and YAG lasers at Nuclear Professional School, University of Tokyo. The compact hard X-ray source can produce tunable monochromatic hard X-rays for 10 - 40 keV. The monochromatic hard X-rays are very useful in large fields of medical and biological sciences. We are planning to carry out dual-energy X-ray CT, which enables us to obtain 3D distribution of effective atomic number Zeffand electron density ρein a matter. The hard X-ray source has an advantage in the dual-energy X-ray CT. The X-ray energy can be changed quickly by introducing a fundamental-frequency and a second-harmonic-frequency lasers. It is indispensable to change the X-ray energy quickly for medical imaging, but it is very difficult to achieve the quickness with a large SR light source and others. The information on the atomic number and electron density will be used for radiation treatment planning as well as for identification of materials in a nondestructive test. We examined applicability of the dual-energy X-ray CT for low to medium Z elements (Z ≤ 38) by considering the X-ray energy profile generated by the Compton scattering hard X-ray source.