Improved tissue staining can help imaging technology peer inside organs without damaging them.

Computed tomography (CT) scanning uses software-based reconstruction techniques to turn multiple 2D X-ray scans of body tissue into detailed 3D images. Researchers from the Technical University of Munich have now developed a procedure that can enhance CT scanning of intricate biological features.

CT scanning often uses contrast agents, chemicals that penetrate specific bioregions to provide a contrasting X-ray signal against a uniform background. The team reports a way to produce CT images with sub-micrometre resolution using a nontoxic organic dye. They improved the uptake of the dye by cell cytoplasm, increasing image contrast, by using acid treatments to render it susceptible to amino-acid bonding.

Experiments showed that the new staining protocol could visualize structures, including an intact mouse kidney, with enough clarity for diagnostic purposes.