X-ray phase contrast can offer improved contrast in soft tissue imaging at clinical energies. To generate phase contrast in a clinical setting without the need for precisely aligned gratings and multiple exposures has traditionally required the use of specialized sources capable of producing x-ray spots on the order of 10 μm in diameter which necessarily require lengthy exposures due to the low intensity produced. We demonstrate results from two systems capable of overcoming this limitation. In the first, a polycapillary optic is employed to focus a typical clinical source to produce a small secondary source of the size required for phase contrast imaging. In the second, a grid of relatively large pitch is used along with Fourier processing to generate a phase contrast image using a large spot size source.
Monochromatic x-ray beams improve image contrast but suffer from low intensity if produced with a flat
monochromator crystal. A doubly-curved crystal makes more efficient use of the source. However, the beam shape
is not conducive to imaging. A combination of a bent crystal followed by a polycapillary optic can be used to
monochromatize and focus x rays to a small spot to perform monochromatic x-ray imaging with good resolution.
Ray-tracing simulations have been developed which account for defects in both optics types. A comparison was
made to measurements of focal spot sizes, angular divergence, and image quality parameters including resolution
and contrast. Simulations support the experimental results that geometric blur is significantly reduced, and
resolution enhanced, for magnification imaging with this optic combination.