The user selects a given size of the field of view before starting the acquisition. This size can be smaller than the size of the Image Detector.
The position of the field of view in the detector area changes during the acquisition in order to focus on an object of interest.
Acquired image is networked or stored in offline media, then the image is:
Displayed and reviewed in cine mode, and the field of view area needs to be displayed on the viewing screen;
Used for quality assurance, to relate the pixels of the stored image to the detector elements, for instance to understand the image artifacts due to detector defects;
Used to measure the dimension of organs or other objects of interest;
Used to determine the position in the 3D space of the projection of the objects of interest.