New technologies in data storage include holographic memory, which boasts storage capacities in the range of one terabyte in a package the size of a deck of cards. There are two main options emerging for long-term storage. First is the conventional archive where the user purchases a tape drive or MOD jukeboxes and houses their archive onsite for the life of the exams. As the PACS grows, so does the size of the archive and the size of the space needed to house it. New alternative solutions include off-site digital storage.
Pricing can be on a cost per megabyte or cost per image basis.
Access to images occurs at the three levels described above. The need for access at each of these storage levels is different. Images on workstation hard drives primarily need to be accessed by radiologists, but may be accessed by clinicians who come to review studies with the radiologist. The near line archive is primarily a buffer between the deep archive and local storage devices, so users don't need direct access to it. Right now at our institution, only the radiologists who are using the workstations on our PACS have access to images in the deep archive.