In our work with hospitals using various PACS systems, we’ve become aware of a common situation which can be solved easily and at low cost with BridgeHead to alleviate tape dependencies.

What’s the Problem?

A PACS receives radiology images in the DICOM format and upon receipt stores them for display and use as part of the radiology workflow. Initially these images are accessed frequently as they are read and a radiology report is generated for use by the referring physician.  As time goes on, these images are accessed less frequently, usually for comparison purposes with more recent radiology procedures as relevant priors.
As a result, there is often an archive process that is scheduled to run periodically on the PACS.  This archive process looks for new DICOM studies that have been received, and archives them to an archive device. The frequency with which this happens varies dependent upon the PACS vendor, but sometime after the DICOM images have been successfully archived to tape, the PACS will remove them from its DICOM cache.  If the images are later needed as relevant priors, the PACS will then retrieve the images from the archive device.

There are usually only a few archive devices supported by a PACS vendor as these devices are required to be validated by the PACS vendor.  The PACS vendor may support more than one media type, but it is still common for existing customers to use a tape library as their archive device.  Another complication is that the customer can only select one media device as their archive device. This can be especially problematic when the archive device is a tape library, and is the heart of the problem: as it means that PACS administrators are burdened with additional tasks associated with tape management.

Details of the Tape Management Chore

What’s involved in managing tapes for a PACS archive? One of the problems with the archive-to-tape method is that DICOM studies are continually added to the tapes in the tape library.  Inevitably the tape library will fill up with DICOM images.  In fact, many hospitals are in the position where they have more tapes with DICOM images than they have slots in their tape library.

It is often not predictable when the tape library becomes full, and the site becomes aware of the situation when the archive process cannot write a DICOM image to the tape library.  At this point someone needs to remove a tape from the tape library, label it, store it, and place an empty tape in the tape library.  Once this process starts, it becomes a regular event for the site as DICOM images are always added, and seldom are removed from the tape archive.

This presents several problems for the hospital:

  • PACS Administrators are typically not trained in the management of tape libraries, causing this problem to fall to the storage or backup administrator.
  • Notification is often done by the PACS in its logs when the archive process cannot write the DICOM images to the tape library.  This requires the PACS administrator to monitor the logs and notify the storage or backup administrator of the problem.
  • Over time, administrators can monitor how often tapes are being replaced, and anticipate when tapes should be replaced before capacity is reached.  This is not an automatic process, however, and may result in some tapes not being filled to capacity.
  • A steady supply of excess tapes must be on hand to handle the ever-increasing amount of DICOM images archived to the tape library.
  • Should the DICOM images need to be recalled, such as when a CD is burned requiring the actual DICOM images, and the DICOM images are on an excess tape, then an administrator will need to find the excess tape and place it in the tape library to access the DICOM images.  This could be a very lengthy process.

In part 2 of this blog series, I will present information on how BridgeHead can easily solve this problem and ease the burden of tape management from any hospital using tape for PACS archive. I will also relate how we did this at a real hospital location this past summer.

In summary, PACS typically archive images only to specific archive devices.  While it is problematic enough to limit choices for archive devices, when the archive device is a tape library, this creates unnecessary burdens for already taxed PACS administrators. BridgeHead’s VNA is a low-cost, easy-to-deploy, and truly vendor-neutral solution for hospitals who want to eliminate their dependency on specific archive devices for PACS DICOM images.