The Additional RT ROI Identification Code Sequence (3006,00B9) is to provide the facility to annotate the ROI with additional codes. Such additional codes are positioned to support cross-institutional, cross-application classification for clinical workflow, automated treatment planning, DVH analysis etc. The code provided in the Purpose of Reference Code Sequence (0040,A170) allows to identify the scope of use of the Additional RT ROI Identification Code (e.g., data registries and clinical trials, cross-institutional, cross-application classification for clinical workflow, automated treatment planning).