Developing a Data-storage Strategy

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James WhitfillCloud-based storage requires evaluation, just as any other storage strategy does, according to James T. Whitfill, MD, CIO of Scottsdale Medical Imaging Ltd (SMIL) in Arizona. “You have to understand how the cloud provider replicates data to different locations, so you trust that there really are multiple copies of those data; that they are kept secure, from a physical perspective; that there are environmental controls, and that your data are not being accessed,” he observes. “Under HIPAA, you must protect that access.”

He asks, “How does that cloud provider guarantee that when you delete those data, if you want to, they are really gone? You think that those data have been destroyed, but can that cloud provider guarantee that they were destroyed?”

So far, Whitfill says, SMIL has not turned to commercial cloud storage, although it remains an option. It can be a very strong option for smaller radiology practices, Whitfill says, and even large practices like SMIL are keeping an eye on the market and the latest storage devices, looking for opportunities to shave expenses and maintain reliability. SMIL installed its PACS in 2003, and its built-in archive has only a year or two left before it reaches capacity; after that, the practice will have to make more decisions about what images and data it needs to store, for how long, and using what infrastructure.

SMIL is a 44-person radiology practice that reads for three Scottsdale Healthcare hospitals and operates 14 imaging centers, including newly opened facilities in Phoenix and Gilbert, Whitfill says. The radiologists read about 300,000 outpatient exams in SMIL’s own network per year; another 350,000 studies are read at the Scottsdale Healthcare hospitals, but SMIL plays no part in the storage of hospital images or data, Whitfill says.

“The hospital PACS and the SMIL PACS are completely separate systems, with different storage archives and different storage databases,” he notes. “The integration is at the network level, where if a radiologist is on an SMIL PACS, he or she can open the hospital PACS on the Web browser, or at a hospital PACS station in an SMIL reading room. In the hospital reading rooms, we have access to the SMIL PACS. If a patient is going to the hospital, and we know in advance, we can export from our PACS to the hospital PACS, and vice versa.”

Whitfill continues, “We don’t have a unified worklist across the two sites today. The solution we have today is not perfect. The added overhead cost and management around a single worklist have stopped us, for now. As CIO of SMIL, my liability is the SMIL PACS. I have no control over the hospital PACS. We do work cooperatively to exchange best practices.” That’s possible because both entities have similar versions of PACS, from the same vendor, he adds.

SMIL’s Storage Needs

SMIL’s image archive is divided into short-term and long-term components, Whitfill says, even though all images remain immediately available online, for now. The long-term archive has about 40 terabytes of capacity. It acts as a backup for the short-term archive, which has 30 terabytes of capacity.

Off-site storage provides an additional 40 terabytes of capacity for replicated long-term data, Whitfill adds, providing an additional layer of redundancy. “We have over 100 terabytes of storage dedicated to imaging, and another 10 terabytes for database servers, billing, and those sorts of things,” Whitfill says.

The imaging archive contains all the CR, MRI, CT, mammography, nuclear-medicine, ultrasound, PET, and dual-energy x-ray absorptiometry studies done at the SMIL imaging centers, Whitfill says. The only thing missing is interventional radiology, since such procedures are only done at the hospitals.

Both the long-term and short-term archives kept in-house use RAID network-attached storage, Whitfill says. He adds that this technology significantly speeds retrieval of images. Using network-attached storage was a step that SMIL took after the price of RAID spinning-disk storage decreased. Initially, the practice used DVD jukeboxes and digital tape for data. Whitfill says, “At that point, years ago, they were much more economical than hard-disk storage, but now, the hard disk is inexpensive enough that we can use it for all the storage.”

RAID storage has another big advantage, Whitfill adds. The RAID boxes can be configured so that even if one or two disks fail, the entire pool of imaging data can be retrieved from the remaining disks.