Hi Lynn,
The dicomcontours object extracts and stores region of interest (ROI) data from the metadata in DICOM-RT structure set files. You can use the object functions to add, delete, display, modify, and create masks from this ROI data. You can learn more about this function in this documentation provided by MathWorks: https://www.mathworks.com/help/images/ref/dicomcontours.html
Hope this helps!