DICOM SOP Classes and associated Information Object Definitions (IODs) are used to convey specific medical imaging information at the Data Format Layer. Examples of such IODs are modality images, patient information, results, etc.

The use of DICOM IODs in conjunction with Media Storage Services forms a number of Media Storage Service Object Pair Classes or SOP Classes. Media Storage Services (e.g., read, write, delete, etc.) shall be performed through the DICOM File Service. The content of the resulting DICOM Files shall be formatted according to the DICOM File Format as specified below.

PS3.4 defines a number of SOP Classes that may be used for Media Storage in Annex I. These SOP Classes are based on DICOM Standard IODs that may be found in PS3.3.

The structure and encoding of a Data Set representing the data associated with a SOP Class shall follow PS3.5. The specification of Transfer Syntaxes that may be used to encode such a Data Set, is also defined in PS3.5.