A projection-based x-ray imaging system combines projection magnification and optical magnification in order to ease constraints on source spot size, while improving imaging system footprint and efficiency. The system enables tomographic imaging of the sample especially in a proximity mode where the same is held in close proximity to the scintillator. In this case, a sample holder is provided that can rotate the sample. Further, a z-axis motion stage is also provided that is used to control distance between the sample and the scintillator.