MicroCT system for small animal imaging with ultrafast laser-based X-ray source

A novel ultrafast-laser-based X-ray source is a promising candidate for replacement of a microfocal X-ray tube in a microCT system for small-animal imaging. We optimized conditions for X-ray generation from a very small (below 5 /spl mu/m) focal spot. We measured X-ray spectra, conversion efficiency, X-ray fluence, and X-ray focal-spot size for a number of solid targets (SiO/sub 2/, Ge, Mo, Ag, Sn, BaF/sub 2/, La, Nd, Gd, Ta, and Pb). X-ray spectra created by ultrafast laser are advantageous for microCT imaging, because most of the emission is in narrow characteristic lines. The spectra can be changed rapidly and matched to the imaging task. They make practical the use of dual-energy microCT with suitable contrast agents and matching targets and filters for low- and high-energy beams. We have obtained images of small animals in single- and dual-energy modes.