The database interface allows establishing relations between stored data objects which can be accounted for in some processing tools and in pipeline processing.
For instance, the tool for MR-based partial-volume correction of brain PET data requires the grey matter, white matter and CSF tissue segments, which can be calculated with an external tool. When this segment image is associated to the PET image, processing is simplified because when choosing PET the corresponding tissue segments are implicit.
Another example is the absolute quantification of a dynamic PET image using a kinetic model which requires information about the tracer activity in whole blood and plasma. Such blood curves can be associated to the PET and their meaning defined by a flag, as explained below.