Chinese Acad Sci, Inst High Energy Phys, Beijing 100049, Peoples R China
; China Japan Fiendship Inst Clin Med Sci, Beijing 100029, Peoples R China
The deflecting angles of X-ray beams caused by refractive objects are deduced according to the refractive process at interface of different refractive indexes. The spacial resolution and the electron density resolution of the diffraction enhanced imaging ( DEI) method are discussed relating to the experimental parameters. Appearances of refractive contrast in the DEI method are discussed and experimentally confirmed. Vivid images of blood vessels in human liver sample are obtained by DEI technique using X-rays with different energies. The contributions of the refractive contrast in improving the image contrast are easily understood.