The ISO 9660 System and Volume Descriptor Area (SVD) from the last session points to the set of ISO 9660 Path Tables and Directory Records that describes the file system of the DICOM CD-R disc. The SVD area starts at the first logical sector of each session and continues through to the first instance of the Volume Descriptor Set Terminator.

Adding, replacing or deleting files from the disc is accomplished by opening a new session and writing within the new session new data (if any), a new set of Path Tables, and Directory Records that reflect the changes, and an SVD area that points to the new set of Path Tables and Directory records.