The principle of IL-XPCI is based on Fresnel diffraction theory which can provide an edge-enhancement effect. Pogany, Gao and Wilkins first established the theoretical formalism for phase contrast image formation of weakly absorbing thin objects [28] . When X-ray beams travel through the object, the downstream beams carry the information of absorption and phase shift. The interaction between the object and the beam can be described by this transmission function