FIGURE 2.

Achieving soft tissue contrast in microCT imaging. Fixed but otherwise untreated, non-mineralized embryo tissue shows only little difference in x-ray attenuation to aqueous mounting media. Thus, its imaging in aqueous media is not applicable. One possibility to increase soft tissue contrast is infiltration of the tissue with a contrast agent containing a high atomic number (Z) compound, thus increasing X-ray attenuation of tissue relatively to the mounting medium (‘staining’). Alternatively, it is possible to decrease X-ray attenuation in the mounting medium by replacing water with ethanol or paraffin, or by drying the embryo followed by imaging of the sample in air. Of all approaches, staining typically yields highest soft tissue contrast.