Image Storage: Blurring the Lines Between Short-term and Long-term Solutions

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Physician wants and needs - as well as budgetary concerns (what else is new?) - often dictate how healthcare organizations structure their data centers and how many of the images are available instantly or even in just a few seconds or minutes. But technology is beginning to make the dilemma less important as image access gains speed.

Three factors are applying great pressure to healthcare organizations as they find ways of storing the data they are producing and gathering on patients: regulations, imaging modalities, namely multislice CT, that are producing larger and larger studies and thus data sets, and increasing physician needs and expectations to get images now. Though technology is a major source of the storage problem, it is obviously also essential to the solution.

For radiology departments in particular, a common model in data storage is to maintain about six months of studies as 'short-term' kept on speedy (but expensive) servers that can call them up in seconds. As data become older than six months, they fall off into the 'long-term' category and are often stored on less expensive technology such as a DVD jukebox, but even these images only take a few minutes to retrieve (although a few minutes can be too long depending on need). And there are ways to fiddle with this scenario so that the waiting period for long-term images is largely invisible.

Such is the case at AnMed Health Medical Center in Anderson, S.C., which is a private, not-for-profit 567-bed inpatient facility. AnMed Health North Campus, located 3 miles from the Medical Center, includes an outpatient center. Having moved to a GE Healthcare Centricity PACS about five years ago, the organization has had an evolving approach to image storage.

In the healthcare world, organizations have to be prepared to store images and supporting data of each patient for a number of years depending on legal requirements. That's a long time if you consider that some of their patients are children. This is driven by a slew of regulations and different authorities dictating how long data must be stored in electronic format.

And the images just keep getting bigger. The organization was the first in the state to convert to all digital imaging, including digital mammography, cardiology imaging, and multislice CT, which all together take up enormous space.

"In 1998, we probably had 20 to 25 servers in our data center. We now have more than 160 servers in our production data center supporting numerous clinical systems," says Marty Stewart, manager of production services. "It was part of that implementation through which we were introduced to the IBM ESS (enterprise storage server) Shark in 1998/99, which is a highly robust disk farm. We currently have two ESS's one located in our production data center and the other located in our disaster recovery center. We are running the IBM PPRC (peer-to-peer remote copy) software that copies transactions at the microcode level from one Shark to another Shark."

As more clinical systems were implemented, they stressed to the vendors that they install all of their applications and databases on the Shark at the main hospital, so the data are instantly replicated to the disaster recovery center located at the AnMed Health North Campus.

Around the same time, they implemented McKesson's Horizon Patient Folder as their electronic medical record (EMR) and this was being stored on several jukeboxes as well, but recently Information Services began archiving this data onto an IBM FastT Storage Server (IBM has since renamed this TotalStorage DS4800). The long term images from PACS were also stored on a jukebox. In 2004, with the jukebox rapidly reaching its capacity, they worked with GE to begin storing long-term images on an IBM FastT. Also, during this time they implemented dual writes for these images (one of a FastT at the main data center, and one to a FastT located in their disaster recovery data center).

All of AnMed's clinical systems connect to the ESS or FastT for their data and applications through their SAN fabric. The SAN "consists of an IBM 2109-M12 Director class switch which can service 128 fiber-attached devices. To connect the AnMed Health North Campus to the AnMed Health Medical Center, we use an ADVA DWDM (Dense Wave Division Mux) on each end of a three-mile dark fiber pair leased from our local phone company," says Tommy Sluder, manager of network & technical support services, part of AnMed's Information Services. "We