Theory
How does a micro-CT work?
The method is based on the visualization of regions of different mass attenuation of the X-rays in the sample. Mass weakening
is the property of a substance to absorb part of the penetrating X-rays and thus to reduce the transmission through the sample.
The attenuation of the X-rays depends on both the chemical composition and the density of the sample. The information on the
locally different X-ray absorptions is displayed as gray values in black and white images.
The X-rays are generated in an X-ray source, sent through the sample and recorded as a 2D projection image by the X-ray detector.
The sample is then automatically rotated a fraction of a degree using a turntable and another X-ray projection image is taken.
This step is repeated until a 180 degree rotation is completed (or 360 degrees, depending on the sample type). Virtual slice
images are then calculated from the X-ray projection images created in this way by the computing process called "reconstruction".
These cross-sectional images can not only be visualized and analyzed, but also subsequently processed into 3D models, films,
physical 3D printed objects or in some other way.
