Design, construction and application of a grating-based X-ray phase contrast imaging system under laboratory conditions

X-ray phase-contrast imaging enables nondestructive visualization of internal structures in weakly absorbing samples, attracting increasing interest for laboratory-based applications. However, translating this technology from synchrotron facilities to laboratory settings requires rigorous parameter optimization to overcome limited source brilliance. In this work, a practical grating-based X-ray phase-contrast imaging system was systematically designed and constructed within a standard laboratory CT chamber. Key parameters, including the grating duty cycle, phase-shift conditions, and geometric constraints, were theoretically optimized to balance fringe visibility and photon flux. The required gratings were fabricated in-house using an optimized lithography and electroplating process. Experimental results using a two-step phase-shifting method demonstrated high-quality imaging capabilities across diverse applications. Specifically, tests on cotton swabs, oxidized 904L stainless steel, and fish bones highlighted the system's versatility in biomedical research and industrial failure analysis. Quantitative analysis revealed that the system significantly enhances feature detectability, achieving a Contrast-to-Noise Ratio (CNR) of 8.5 for biological microstructures—an approximately 7-fold improvement over conventional absorption imaging (CNR 1.2). This work provides a reproducible framework and validated parameter set for implementing high-sensitivity phase-contrast imaging under accessible laboratory conditions.