Query/Retrieve (C-FIND and C-MOVE)
Query/Retrieve is the pair of DICOM services used to search what a remote device holds and then pull matching studies from it: C-FIND performs the search and C-MOVE transfers the results.
What Query/Retrieve (C-FIND and C-MOVE) means in practice
The two are deliberately separate. C-FIND returns matching records at the patient, study, series or instance level so a user can see what exists before moving anything, and C-MOVE then instructs the remote device to send chosen studies to a destination. This is how a viewer pulls a prior study from an archive, as opposed to C-STORE, where the sender decides to push.
Source
This definition follows NEMA PS3.7 §9.1.2 (C-FIND) and §9.1.4 (C-MOVE); service class in PS3.4 Annex C, published by NEMA as part of the DICOM standard.
Related terms
C-STORE
C-STORE is the DICOM network service used to transfer a composite object — an image or similar instance — from one device to another, and it is the operation behind "sending a study" to a PACS.
PACS
A PACS is a system that stores, retrieves, distributes and displays medical images, connected to imaging modalities and viewing workstations over a DICOM network.
Patient, Study, Series and Instance
DICOM organises imaging data in a four-level hierarchy: a Patient has Studies (one imaging visit each), a Study has Series (one acquisition run each), and a Series has Instances (the individual images or objects).
Storage SCP
A Storage SCP is the role a device plays when it accepts incoming DICOM images, listening for C-STORE requests and storing what it receives — the role a PACS or an archiving viewer performs.
Related on this site: Querying studies on a SoftDicom device.