3.2. Imaging Modalities. Imaging technology has improved considerably since
the end of the 19th century. Many different imaging techniques have been developed
and are in clinical use. Because they are based on different physical principles [41],
these techniques can be more or less suited to a particular organ or pathology. In
practice they are complementary in that they offer different insights into the same
underlying reality. In medical imaging, these different imaging techniques are called
modalities.