Micro cone-beam CT scanner based on X-ray polycapillary optics

In-vivo small animal imaging system is an important part of disease research and new drug development. Itis essential for living small animal imaging system to be able to provide the anatomical structure, molecular andfunctional information. The X-ray micro cone-beam computed tomography (micro-CBCT) can performlongitudinal study with a resolution of tens-to-hundreds of microns in a short imaging time at a relatively lowcost. Furthermore, it is easy to combine with other modalities to provide abundant information about smallanimals. A key challenge to the micro-CBCT scanner is that its spatial and contrast resolution determinedprimarily by the X-ray focal spot size, the detector element size, and the system geometry. Aiming to improvethe spatial resolution, contrast resolution, and imaging uniformity of the micro-CBCT system, we use the X-raypolycapillary optics for adjusting the X-ray source. A micro-CBCT based on X-ray polycapillary optics with alarge field of view is constructed for the small animal imaging study. The micro-CBCT system is composed ofmicrofocus X-ray tube with an attached polycapillary focusing X-ray lens, amorphous silicon-based flat paneldetector, rotation stage, and controlling PC. The Feldkamp-Daivs-Kress (FDK) algorithm is adopted toreconstruct the image. The system performances are evaluated. The magnification of this micro-CBCT system is1.97. The results show that the spatial resolution of the system at 10% modulation transfer function (MTF) is9.1 lp/mm, which is 1.35 times higher than that in the case of no optics. The image uniformity deteriorationcaused by hardening effect is effectively alleviated by filtrating the low energy X-rays with the X-raypolycapillary optics and the contrast enhancement is more than twice. The anesthetic rats are imaged with thismicro-CBCT system in vivo and the practicability of the system in small animal imaging research is verified