Element‐specific microtomographic imaging of Drosophila brain stained with high‐Z probes

An application of X‐ray microtomography to the Drosophila adult brain stained with colloidal gold and a platinum compound is described. The transparency of biological tissue to hard X‐rays enables tomographic visualization of the three‐dimensional structure of tissue entrails. Each high‐Z element was visualized as a three‐dimensional structure from the difference absorption coefficient image at the corresponding L_III absorption edge. The cortex of the optic lobe was selectively visualized by the specific adsorption of colloidal gold. The entire structure revealed by the platinum impregnation allowed the anatomical assignment of the gold‐stained structures. Selective staining and specific visualization of biological tissues at micrometer resolution should elucidate the three‐dimensional cellular organization essential for the understanding and application of biological microstructures.