DVD-RAM, DVD-R find a home in healthcare

Posted on February 01, 2002

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Advantages include low cost, media removability and durability, and random access.

By Kirk Wilson

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Every aspect of healthcare management is changing rapidly, with managed care and integrated delivery systems placing increased emphasis on information management. The goal for every healthcare facility and practitioner is to develop and implement a consistent multimedia, computer-based patient medical record (CPR) that can be available throughout the organization and easily interfaced with other reporting and record-keeping systems.

The goal is to have a CPR system that will enable authorized individuals in the healthcare facility to record, monitor, retrieve, and analyze every encounter with patients. The system should also provide a secure interface with partners and systems outside of the facility.

Because of the rising cost of healthcare, limited resources, increased budgetary constraints, and growing pressure from the government and private sectors, hospitals, clinics, and private practitioners need fast and reliable means of processing, storing, retrieving, and sharing data. According to the Department of Health, Education, and Welfare, the healthcare industry spends more than $100 billion a year just in processing paperwork.

As a result of using paper and film technology, almost one-third of patient records for all medical appointments are lost. Nearly 35% of prescription refills are never recorded. Using these technologies is labor-intensive, time-consuming, and expensive. In fact, the average cost of finding a paper-based medical document is about $15.

Digital storage is quickly spreading throughout the industry, and in the near future, physicians will be able to gain access in a matter of seconds to the entire medical history of a patient they treated years ago, including X-rays, handwritten notes, or spoken explanations from other doctors, pharmacy and hospital records, photos, and videos.

High-capacity storage that provides fast access and scalability has become a key requirement in this environment. The situation is particularly critical in the healthcare industry because of the growing use of multimedia applications. In addition to storing X-rays and other images digitally for medical and dental applications, video is being used for education, training, and documentation.

Approximately two billion radiographs are taken around the world each year. When X-ray films are converted to digital format, the key concern is not storage capacity requirements but the assurance that no vital clinical information is lost.

According to the American College of Radiology, converting a conventional radiograph to a storable digital format requires 10MB of storage capacity. Theta Consulting estimates US consumption of 1.7 billion square feet of medical X-ray film to perform more than 310 million procedures each year. All of this data must be maintained by the healthcare facility for near-online access for a minimum of seven to 10 years.

Role of DVD

Because of the growing need for reliable, low-cost storage, two DVD standards have become widely used by Radiological Society of North America (RSNA) members-DVD-RAM and DVD-R. DVD-RAM is randomly rewritable, like a hard drive, making it a good choice for many CPR applications where data must be revised, updated, and added. DVD-R media, on the other hand, is a write-once technology that provides an unalterable, archived history of patient care. Both technologies store 4.7GB of digital data on a single-sided disc, at less than $0.01 per megabyte.

Healthcare and RSNA officials have found DVD-RAM and DVD-R appealing because the technologies were designed for both data and video applications. Backed by nearly 300 members of the DVD Forum, the technologies also have a capacity growth path from the current 4.7GB per side to more than 50GB per side. At the same time, the standards provide backward-compatibility to ensure there is read support for at least two generations of media.

DVD-RAM and DVD-R provide removable storage with 30- and 100-year data lives, at relatively low cost. DVD is often used in healthcare applications that are designed around server-based libraries. These applications require relatively modest access times (<10ms), combined with high capacities and data-transfer rates.

To provide easy exchange of data, the DVD Forum set down the requirements that write-once DVD could be read by virtually every DVD device. While DVD-RAM discs can be read by a number of different DVD-ROM drives and DVD players, healthcare industry officials feel more comfortable forwarding CPR documents and data on DVD-R media because the archival medium doesn't allow for accidental or purposeful modification or alteration.

Evolving requirements

While the digital storage of X-rays is logistically and financially compelling, most healthcare institutions have gone beyond simple radiology and moved to diagnostic imaging. The evolution was fueled not only by new imaging technology but also by advances in computer hardware, software, and storage.

Rooms full of X-ray film are being replaced with high-density DVD libraries that provide a terabyte of storage in one square foot. Images and other data in the computer-based patient medical record are being stored as objects in the data repository. The DVD libraries are connected to the hospital's information management system, and any file-regardless of its age-can be retrieved by authorized personnel almost instantly.

According to the US Department of Commerce, the US healthcare system spends up to $7 billion per year on film alone. It is estimated that the average radiology department generates about 18GB per day and more than 4TB per year.

The standards established by the DVD Forum are complemented by standards within the healthcare industry.

The value of standards

To meet the growing requirements of medical imaging, the RSNA established DICOM (Digital Imaging and Commu nications in Medicine) nearly 15 years ago. DICOM is the industry standard for the transfer of radiological images and other medical information between computers. The standard enables digital communication, storage, and retrieval between diagnostic and therapeutic equipment and systems and has also improved the delivery of cost-effective healthcare.

Because of the open-standard guidelines, the time required to capture, store, and share medical information has been reduced, enabling physicians to make accurate diagnoses and treatment decisions more quickly.

The DICOM standards have become the dominant method for producing, capturing, storing, and communicating all types of medical images and patient data. As a result, CPR technology has evolved to the point that all relevant patient information can be stored online for access at any time by authorized care providers. All of the CPR data components (e.g., text, images, video, audio, and documents) are increasingly being acquired, transmitted, visualized, and stored in compliance with the DICOM standards.

Most healthcare institutions' picture archive and communications systems (PACS) are based on 10Mbps Ethernet or 100Mbps Fast Ethernet. The networks are being enhanced with intelligent hubs and programmable switches to efficiently and effectively handle image traffic. Remote access is being supported by DSL, T1, or FDDI high-speed Internet access.

These systems provide support for digital film-less management of patient folders that contain the cumulative history of the patient's care. All of the pertinent patient data and metadata is migrated to the centralized data repository so it can be made available to all authorized users-locally and remotely.

The architecture supports standards such as NFS, IPX, TCP/IP, and FTP as well as appropriate ISO protocol levels such as HL7 and DICOM. Because the number of workstations querying the system and the volume of storage under management vary widely, the DVD libraries may have to scale from one to hundreds of terabytes.

To meet these high-capacity storage requirements, libraries that incorporate 4.7GB DVD-RAM/R drives provide a cost-effective solution for institution-wide data-warehouse storage requirements. High- capacity libraries typically incorporate four to six drives, with each drive providing 4.7GB of data under the head. In addition, the DVD-RAM/R drives provide the scalability to support growing storage needs. For example, users can divide their data-warehouse requirements into manageable segments by daisy-chaining multiple 50-slot (470GB) to 200-slot (nearly 2TB) libraries. This provides high-speed, random access across 16 to 24 DVD-RAM/R drives and minimizes physical media swapping, which can slow perfor mance and cause thrashing-induced failures. The average cost per terabyte is usually about $100,000 to $150,000, including media.

With the drives' 5MBps transfer rates, healthcare IT managers can achieve transaction rate performance comparable to a low-end RAID array at a cost approaching tape. Combined with RAID and middleware such as hierarchical storage management (HSM) software, a DVD-RAM/R datamart or warehouse can provide the following advantages:

  • Scalable, low-cost random access and media removability;
  • It serves a dual function when implemented as a disaster-recovery and backup option. A DVD-RAM or DVD-R disc can be loaded and data restoration started in about 15 seconds;
  • DVD-RAM/R media are more reliable than magnetic storage. DVD-RAM/R media life is measured in decades, not years, and the risk and cost of losing data to a head crash are non-existent;
  • It is less expensive yet slower than RAID and faster but more expensive than tape and provides a longer data life; and
  • It has a relatively low duty cycle, which enhances reliability.

The healthcare industry's drive to implement data warehousing helps institutions maximize the value of their data. By becoming the organization's enterprise-wide information exchange facilitator, the central repository enables authorized healthcare professionals to share information to improve diagnostic decision-making while controlling costs. Data warehousing consolidates data previously distributed across incompatible departmental servers into a single, compatible database.

The re-centralization of volumes of data into a single, managed database has not only increased storage capacity requirements, but also it has placed even greater emphasis on minimizing the risk of data loss. DVD will continue to expand its presence in the healthcare industry because it provides a balance of high capacity, low cost, adequate performance, media durability, and high availability.


Kirk Wilson is director of operations at Asaca (www.asaca.com) in Golden, CO. He can be contacted at kirkw@asaca.com.

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