Principles of computed tomography

Computed tomography (CT) is a powerful medical imaging technique, based on the measurement of x-rays transmitted through an object, able to represent the morphological and anatomical information of a human body section. Since its introduction in the first 1970s, CT has experienced a dramatic evolution in terms of resolution (minimum size of a distinguishable object), scanning time (time necessary to acquire all the measurements) and elaboration time (time to process the measurements through a computer).This chapter aims to report on the basic working principles and hardware components of CT. In the last section, emphasis is focused on spectral CT, which improves the technique performances in terms of chemical tissue characterization.