Scanning Preparation #2: Sample Composition

The atomic composition of a sample has a major effect on the quality of microCT images of that sample. As discussed in the Interaction of X-rays with Matter section, higher atomic number (Z) materials block, or attenuated, more X-rays from passing through the sample. The same is true for the density and thickness of the material. The X-ray attenuation of different materials in a sample is measured by the X-ray detector and represented as the contrast between phases in a microCT image (i.e. tomogram). With X-ray attenuation in mind, some sample compositions can prove problematic for microCT imaging:

1. Large concentrations of high-Z materials (e.g. metals)
2. Material phases with similar X-ray attenuation in the same sample