Functional modalities, on the other

Functional modalities, on the other hand, depict the metabolism of the underlying
tissues or organs. They include the three nuclear medicine modalities, namely,
scintigraphy, single photon emission computed tomography (SPECT) and positron
emission tomography (PET, Section 3.2.4) as well as functional magnetic resonance
imagery (fMRI). This list is not exhaustive, as new techniques are being added every
few years as well [13]. Almost all images are now acquired digitally and integrated
in a computerized picture archiving and communication system (PACS).