A lot of research on laser produced x-rays has been carried out here, exemplified with an image of a rat. Very fine details can be resolved due to the small x-ray source. See e.g. A. Sjögren et al, Rev. Sci. Inst. 74, 2300-2311 (2003) for further information on this experiment.
X-rays are produced when the laser is focused on a thick solid target. In this case, a rotating disc of tantalum.