Professor J. N. Anker (Clemson University, South Carolina, United States) and his colleagues have recently reported an interesting application of optical luminescence excited by X-rays. So far, the spatial resolution of conventional florescence microscopy for tissue has been fairly limited. This is mainly due to the spread of the excitation light, which is scattered by the sample itself, particularly in the case of thick tissue. The novel idea is to use X-ray excited optical luminescent light from the scintillator plate placed at the back of the tissue. X-rays are not scattered very much even in thick tissue, and such a small spread leads to high-resolution chemical imaging of the tissue. The authors demonstrated an interesting application as a pH imager using methyl-red dyed paper. For more information, see the paper, "High-Resolution Chemical Imaging through Tissue with an X-ray Scintillator Sensor", H. Chen et al., Anal. Chem., 83, 5045 (2011).
