As health care facilities increasingly turn to digital imaging, with the ability to move images around the hospital or around the world instantly, the less glamorous side becomes figuring out how to store those large sets of images in a way that is easily accessible and protected from network failures. Physicians want to access the images they need instantly; facility administrators must archive images for the long term and then recover them when disaster strikes, all while keeping costs down; and information technologists want a system that is easy to maintain. No single solution exists; it is a mix of hardware and software tailored to the needs and budget of each facility by a myriad of partnerships between companies.

Equipment Options
“Several years ago, when the PACS [Picture Archiving and Communications System] was starting to boom in the major medical centers, many were implanting these expensive PACS solutions, but they didn’t realize the storage capabilities necessary to drive them once they implemented them,” says Jon Mello, director of global health care solutions at EMC Corp (Hopkinton, Mass). “Storage has become a very important aspect of the whole solution.”

The storage solution requires close relationships between various hardware and software vendors to provide the large digital storage space health care images need as well as the workflow tools that make the images manageable and accessible. Despite the numerous arrangements available, in general, facilities are turning to a multilayered approach that involves both short-term and long-term storage.

Studies have shown that most images are used within the first year. After that, only about 1% of images are ever accessed. Therefore, many facilities are using a short-term storage option that makes recent images available quickly while storing older images on media that are less expensive but require a few minutes to access. A variety of methods exists to create short-term or “online” storage, including sophisticated systems using network-attached storage (NAS) or storage area network (SAN) solutions. However, these are all essentially interim storage devices using magnetic or “spinning” disks that allow physicians to access images within seconds. Many companies are using and talking about the amount of storage available in terms of Redundant Array of Independent Disks (RAID), a collection of drives that can operate independently but together act as a single storage system.

But “spinning disks” are expensive, so older images are archived on a less-expensive medium—generally tapes or, increasingly, DVDs that are stored in a “jukebox.”

Nancy Fisher, vice president of Data Distributing LLC (Laguna Hills, Calif), a turnkey supplier of archival imaging storage, says she believes DVDs will become more popular than tape media in the future because of the increasing prominence of DVD drives worldwide.

“People don’t want to invest something so delicate as the storage of patient data and images in a medium that might not be around in a couple of years or that keeps changing,” she says.

She added that eight to 10 different types of tape media and their drives exist so that sharing tapes becomes more difficult. DVDs (DVD-R in particular) are an increasingly accepted format found in homes and personal computers, making the sharing of information easier.

Whatever the medium, the jukebox-stored image can be accessed automatically and pulled up on workstations just like younger images, but because the images must be retrieved from the jukebox, it can take a few minutes. For physicians, those few minutes add up.

Facilities, then, try to have enough disk space available to keep images “online” for as long as possible. “In the last couple of years, people have tended to store more and more of their data online,” says Kobi Margolin, vice president of marketing at Algotec Inc (Duluth, Ga). “Two years ago or more, we used to offer systems with 2 to 3 months’ worth of online storage. Nowadays, the trend is to come up with 6, 12, or more months’ worth of online storage. The main driver for that has been the reduction in the cost of magnetic disks. They’ve dropped considerably, and the prices are continuing to drop.”

As prices fall, the idea of storing all images on the faster interim storage rather than sending older images to tape has begun to circulate. That solution appeals to Brad J. Block, CIO at Doylestown Hospital in Pennsylvania. The facility, which performs about 50,000 studies per year at the hospital and an outpatient center, currently uses a mini–PACS with RAID storage that can hold 60 days’ worth of images. The facility is switching its long-term storage from tape to DVD, which will provide 3 years’ worth of additional storage while it works toward implementing a full PACS in the next few years.

“Whenever you access secondary storage, regardless if it’s DVD or tape, it takes longer to retrieve that information,” Block explains. “So why don’t we install a server with more disk capacity, especially now with the price of storage coming down, and utilize a backup server for contingencies? Why do you have to go to secondary storage?”

You don’t, according to EMC, which has introduced Centera, a long-term storage device that uses disks to allow automatic retrieval when the radiologist needs it. Centera costs 4 cents per megabyte—compared with a tape’s 1 cent per gigabyte—but EMC officials say Centera’s ease-of-operation features require fewer employees to maintain, which helps lower overall costs.

EMC’s Centera is a long-term storage device that provides for easy data retrieval when radiologists need it.

While Centera is receiving rave reviews from some, others say the cost difference between disks and other media, such as tapes, for long-term storage is still too expensive. Richard Amador, PACS product manager for Canon Medical Systems Inc (Irvine, Calif), says facilities also have to factor in the cost of backing up disks to appreciate the difference in price between online storage and jukebox archiving.

“It’s only a matter of time before that hardware will fail. It’s not if, it’s when,” he says. “So you have to plan for a hardware failure of the data that you’re trying to preserve. When you look at all of these other components that you need to make the overall system as reliable as possible, spinning disk becomes a lot more expensive.”

Amador says the multilayered approach of providing as much online storage as is economically possible while archiving the images on a jukebox is a happy medium that works well for most facilities.

Beyond Hardware
Software also plays a key role in managing stored digital images, and facilities have a variety of options to choose from that serve a number of needs. “The problem is if you have 150,000 images and you put them in a SAN, it’s like putting 150,000 images in a shoebox,” says Tim O’Connor, director of product management at Teramedica Inc (Milwaukee, Wis). “How do you know which image is what when you need to go back and get it within a split second?” Teramedica is one software company that gives facilities a way to map all of those images across a storage infrastructure for easy data integration, access, and distribution.

Other workflow tools automate a number of functions for easier maintenance and access, including duplicating images onto the jukebox in addition to storing them online; dropping images off the interim storage disks after they have reached a specified age to make room for new images; and, if the system is integrated into a RIS, anticipating the need for images—such as when a patient is scheduled for a new scan—by using prefetch tools that bring previous images “online” from the jukebox before the physician needs them.

Software solutions also automate redundancy in the storage system, a vital component that every facility must provide, experts say. Disaster recovery can be an onerous, expensive burden, but regulations require long-term image archiving as well as a plan in case disaster strikes and the original image is lost.

Paul Unkel, director of Inturis for Radiology at Philips Medical Systems North America (Bothell, Wash), says too many facilities rely on online storage without sufficient backup solutions, particularly as SAN and RAID become more popular. “If you have a catastrophic problem, and you will because RAID is going to fail, you have no hard backup,” he says. “You need to copy the data onto some type of hard media that you can take away and put in a safe place.” In addition to duplicating images from online storage, most vendors suggest duplicating tapes as well and storing the extra tape at a different location.

This image, captured with Emageon’s Advanced Visualization, illustrates the huge data sets requiring storage.

One duplicate copy is not enough for Sean Moynihan, director of information systems for the Department of Radiology at the University of Virginia Health System (Charlottesville). “Anything could happen,” he says. “I tried to cover as many bases as I could. I haven’t seen too many sites with the redundancy that we have designed into this system.” At Moynihan’s facility, the RAID image is mirrored onto another disk at the hospital, then both copies are duplicated onto a second RAID system at another site about three quarters of a mile away. That day, one of the RAID copies is duplicated onto the tape jukebox; that night, the taped copy is duplicated yet again and eventually stored at a third location.

Also, the hospital is developing a process to test the backup, switching from using one site’s RAID system to the other site’s monthly. “What fails most of the time on a disaster and recovery plan is people never test their backup,” Moynihan says.

The facility performs 380,000 procedures a year. About 75 days’ worth are stored on EMC’s online RAID storage and StorageTek’s (Louisville, Colo) jukebox. But like many IT directors nationwide, Moynihan says one of his primary goals is to extend that amount of RAID to hold a year’s worth of images. “We’ve found that [we] can spend most of [our] time doing retrieves, especially for late show-ups and unscheduled patients, and not optimizing the radiologist’s time,” he says. “It’s extremely critical to have those studies available as soon as possible.”

Moynihan prefers tapes for long-term archiving because the cost of spinning disks is still too expensive. A 35-gigabyte tape costs just $60, but a 36-gigabyte disk drive he recently purchased cost $2,000. “The economics just aren’t there yet,” he says.

Like many IT directors nationwide, Moynihan says he plans to expand his PACS infrastructure to the entire institution by the spring. In many facilities, different departments are managing and storing their own images, particularly in cardiology and radiology. PACS companies are now or will soon be providing the hardware and software necessary to integrate different departments into one networked system for easier IT management and to lower overall costs. “More and more, the CIOs are looking at how they can consolidate all of the image storage needs of the different departments that they deal with,” says Vishal Wanchoo, vice president of imaging and information systems at GE Medical Systems (GEMS of Waukesha, Wis).

Teramedica’s O’Connor says integration is a trend that will continue to expand. “The images aren’t images anymore; they’re data. Those data need to be shared across the enterprise,” he says. “Almost every medical specialty uses some form of imaging today. Imaging will be integrated completely throughout all tasks and processes in the hospital. I think the future of image management in a hospital system is that image data will become as prevalent as laboratory data anywhere in the institution.”

Data Distributing’s Nancy Fisher recommends the Pioneer DRM-7000 FlexLibrary, a 720-disc DVD jukebox with two drives, for medical imaging storage.

Storage Service Providers
Canon’s Amador calls it the “Switzer- land of archiving”: a neutral third-party application service provider (ASP) that stores a facility’s images at an off-site location. The facility pays for the service on a volume basis rather than worrying about buying, maintaining, and upgrading the hardware and software of storing the images themselves. “A year ago, I would have told you that you’d be crazy to sign up for it—because from a cost standpoint, I can sell people a jukebox that scales anywhere from 1 terabyte to 50 terabytes, and the cost per exam is literally pennies or less,” Amador says. But he adds that it can provide peace of mind and a painless, easy-to-understand method for facilities to store their images if they are willing to pay.

Despite ASPs’ hype a few years ago, using an off-site primary data center did not take off in the market as many predicted. Doylestown Hospital’s Block says he would welcome an ASP–based storage solution because it would take care of all of his storage needs, including backup. “It really reduces the day-to-day operational load of the system,” he says. “I’m a fan of the ASP model; however, it will not be cost-effective for Doylestown until we cross the bridge to a full PACS environment.”

Cost, as Amador suggests, is one reason. But Block cites another: the radiologists. “In my organization, the IT side of the house would favor ASP,” he says. “But the clinical side of the house is very queasy about ASP because they feel it’s some image in the sky somewhere that they can’t see or feel.”

Patrick Boyle, segment executive of medical imaging for IBM Life Sciences, a division of IBM Corp (White Plains, NY), agrees that cost and lack of familiarity with the concept, as well as the difficulty of providing a fast response time through earlier telecommunication lines, initially hindered the ASP–based off-site storage market. But, he says, ASP has found a niche. “One by one, these issues are going away. [Facilities have] seen the success in other industries, and they’re starting to feel more comfortable with it,” Boyle says. “There’s been a huge increase in the number of customers that use off-site storage services for disaster recovery. Unfortunately, tragedies like 9/11 cause businesses in all industries to look at what their capabilities are for recovering from a disaster.”

Boyle says he is not convinced that ASP storage services cost more in the long run, citing not just hardware but floor space, personnel to operate and maintain the system, and the utilities to run the equipment—in short, a host of other factors. “Sometimes it’s very difficult to compare the return on investment between what it costs me to own it and what it costs me to rent it,” he says. Although an ASP should be a consideration for every facility, Boyle adds, organizations that might benefit the most include facilities with a limited IT staff, a restricted capital expenditure budget, and unpredictable storage requirements in which growing as needed might be less expensive if purchased as a service.

GEMS’ Wanchoo says that ASP– based off-site storage is best suited for smaller facilities that do not have the capabilities to provide the storage on-site. “Off-site storage provides customers with a very good fail-safe option for disaster recovery,” he says. “If a hospital doesn’t even have a second data center, they really can’t do effective disaster recovery.” GEMS’ ASP business has been expanding by about 45% each year for the last few years as primary storage for small facilities and as secondary storage for disaster recovery.

Gary York, PhD, CTO and founder of Emageon Inc (Birmingham, Ala), says that the ASP model has expanded to include on-site storage as well. Companies like Emageon put their hardware within the facility and continue to maintain and upgrade equipment on-site. The facility still pays per volume, so it receives the same benefits of paying for the service rather than the equipment but without the concerns of sending the images outside the facility.

Some large facilities are setting up their own off-site storage networks, York says. Kaiser Permanente (Oakland, Calif), for example, is setting up a single long-term storage system for all of its sites, which range from large hospitals to small imaging centers. The 6 million images generated each year will be stored in Kaiser’s own centralized data center. Emageon is helping to set up the system, but Kaiser will run the network. According to York, “Institutions are saying, ‘Managing images is a difficult problem, and it makes sense for us to take that burden off each of our individual hospitals; we can reduce our costs by centralizing that service and managing it ourselves.’”