Backing up PACS: ASP not, want not

Application service provider (ASP) models let radiology departments focus on image generation and interpretation while outsourcing nonclinical work such as image storage, retrieval, and distribution.

ASP models are also used for PACS backup and disaster recovery. Last year, Saint John's Health Center in Santa Monica, CA, integrated an ASP model archive solution for short-term backup of clinical PACS image data.

The ASP backup archive provides instantaneous, automatic backup of acquired PACS image data and instantaneous recovery of stored PACS image data all at a low operational cost and with little human intervention. This solution can be used for both scheduled and unscheduled downtime that occurs on the main PACS archive.

"The ASP backup archive holds a specific amount of PACS data acquired by a hospital offsite utilizing the ASP model," said Brent Liu, Ph.D., previously Saint John's PACS administrator and now PACS implementation manager at the University of California, Los Angeles Medical Center. "During a disaster event, PACS data can be easily exported from the backup archive server offsite directly into the hospital PACS via the DICOM protocol."

Radiologists can thus continue to read with historical studies until the onsite archive has been reestablished.

The hospital is connected via some broadband connectivity (preferable a T1 or higher service line) to an offsite location where the backup archive server is located.

"The backup archive server is 99.999% fault-tolerant, making it a continuously available server," Liu said.

If a disaster occurs at the hospital where the onsite archive is destroyed and the connectivity is preserved, the PACS can query and retrieve directly from the backup archive server offsite for historical studies. In the event connectivity is lost, a portable data migrator can be used to export the PACS exams from the backup archive server and physically brought to the hospital. The PACS exams can be imported directly into the hospital PACS the same day.

Requirements include:
? an offsite location
? an additional PACS server as a backup archive, preferably with continuous availability
? a broadband connection (T1 or better) between the hospital and the offsite location
? two DICOM gateways at each site to buffer the transmission of PACS exams between the two sites

DICOM protocol is utilized to import and export the PACS exams as well as for storage.

The ASP model works for applications other than disaster recovery.

"The ASP backup archive solution can also be used as a temporary archive during scheduled downtime events to the onsite PACS archive, such as preventative maintenance or software upgrades, so that radiologists can have access to historical PACS exams even though the onsite PACS archive server is down," Liu said.