Positron emission tomography–computed tomography (better known as
PET-CT or
PET/CT) is a
medical imaging technique using a device which combines in a single gantry system both a
positron emission tomography (PET) scanner and an
x-ray computed tomography (CT) scanner, so that images acquired from both devices can be taken sequentially, in the same session, and combined into a single superposed (
co-registered) image. Thus,
functional imaging obtained by PET, which depicts the spatial distribution of
metabolic or
biochemical activity in the body can be more precisely aligned or correlated with anatomic imaging obtained by CT scanning. Two- and three-dimensional
image reconstruction may be rendered as a function of a common
software and control system.