There are several instances in which a PACS vendor or user needs to migrate patient data from one PACs digital image archive to another (e.g. storage hardware upgrade, PACs replacement of same or different vendor).

When a legacy PAC system is replaced with a newer PACS system, all patient data stored on the old system needs to be migrated to the new one. This operation must be done while both systems are in normal use. When all data has been moved, the old system is de-installed.

Typically, one needs to perform the data migration operation within a narrow time-window during which new patient data is archived into the new system while old data continue to be retrieved from the old system. The objective is to minimize the size of this window without adversely impacting the performance (response time) of the systems.

Our Solution

DSI has developed a scalable and flexible solution to patient data migration between PACS systems, the DICOM BRIDGE.

Two versions of the DICOM BRIDGE are available:

• The PACS-to-PACS DICOM BRIDGE (P2P-DBridge),
• The PACS-to-Tape-to-PACS DICOM BRIDGE (P2T2P-DBridge)

The P2P-DBridge is an application, running on a Windows 2000 workstation (the DBridge Workstation) networked with two PACS systems, that acts as a DICOM client to the two DICOM servers and ‘moves’ patients data from one system to the other.

The P2P-DBridge queries the source PACS to generate the ‘patients/studies list’ used to drive the data migration process. All data archived in the source PACs or any subset, based on specified selection criteria, can be migrated to the target PACS.

The data move operation is throttled in such way that it does not impact the normal operation of the PACs systems. A flexible transfer rate control mechanism provides for automatic adjustment of the transfer rate based on the load of the PACS. At the end of the process, the P2P-DBridge verifies that all patients’ data has been transferred successfully by querying the target PACS system.

In the case of large (or multiple) PACS digital image archives, multiple P2P-DBridge workstations can be used. A P2P-DBridge Workstation can operate unattended, while the data migration process is monitored via periodic reports generated by the workstation.

Since the P2P-DBridge is implemented as a fully compliant DICOM Client, it can migrate data between PACS systems of the same or different vendors and is independent from the type of data storage technology used in either the source or the target PACS server.

The P2T2P-DBridge is an application, running on a Windows 2000 workstation (the DBridge Workstation) attached to a mini tape library. Two workstations are used to perform the data migration.

One workstation (the P2T-DBridge workstation) is networked with the source PACS system and acts as a DICOM client. The P2T-DBridge queries the source PACS to generate the ‘patients/studies list’ used to drive the data migration process. All data archived in the source PACS or any subset, based on specified selection criteria, is migrated, in the form of DICOM datasets, from the PACS system to magnetic tapes.

The other workstation (the T2P-DBridge workstation) is networked with the destination PACS system and acts as a DICOM client that ‘moves’ the patient’s data, in the form of DICOM datasets, from the magnetic tapes to the PACS system. At the end of the process, the T2P-DBridge verifies that all patients’ data has been transferred successfully by querying the target PACs system.

The tapes used as temporary storage of the patients data are “transferred” from the library attached to the P2T-DBridge workstation to the one attached the T2P-DBridge workstation.

This approach is used when the source and target PACS are geographically apart and the connecting WAN doesn’t have enough bandwidth, or the ‘unloading’ of data from the source PACS cannot be performed in parallel with the ‘loading’ of data into the target PACS.

As in the case of the PACS to PACS migration, the data move operation is throttled in such a way that it does not impact the normal operation of the PACS systems. A flexible transfer rate control mechanism provides for automatic adjustment of the transfer rate based on the load of the PACS.

The data migration service includes the optional updating of the source PACS database to reflect the new location of the patient’s data.