Tomographic imaging of coherent X-ray scatter momentum transfer distribution using spectral X-ray detection and polycapillary optic

Quantitation of coherent x-ray scatter traditionally involves measuring the intensity of the scattered x-ray over a range of angles (θ) from the illuminating monochromatic x-ray beam. Spectral x-ray imaging produces the same information at a single θ when bremsstrahlung x-ray exposure is used. We used a 200μm thick sheet-illumination of a phantom (lucite cylinder containing holes with water, polyethylene, collagen, polycarbonate, and nylon) and a polycapillary x-ray optic collimator to provide measurements at a fixed θ. A Medipix2 x-ray detection array (256² (55μm)² pixels) provided the spectral (E, 10 - 22 keV in 3keV energy bins) spread needed to generate the momentum transfer (q) profile information at one angle. The tungsten x-ray source anode (aluminum filter) was operated at 35kVp at 20mA. The detected scatter intensity was corrected for attenuation of the incident and the scattered x-ray by use of the regular CT image of the phantom generated at the same energy bins. The phantom was translated normal to the plane of the fan beam in 65, 0.2mm, steps to generate the 3D image data. The momentum transfer profiles generated with this approach were compared to published momentum transfer profiles obtained by other methods.