Adding Sequence Items
A sequence in DICOM is represented by DicomDataSets Object in DicomObjects and a sequence item is represented by a DicomDataSet Object.
DICOM allows a dataset to contain other nested datasets, which are encoded as “sequences”. The point of this structure is to allow repeating groups of data, so whilst such sequences often only contain a single dataset, the format is defined such that each sequence consists of a set of datasets. Of course, this structure lends itself perfectly to recursion, and some DICOM IODs such a Structured Reporting and the Radiotherapy Extensions can use sequences nested 5 or 6 deep !