Holographic storage: flash of brilliance or flash in the pan?

Enthusiasm over the acquisition and distribution benefits of PACS and its attending imaging modalities is soon followed by a sobering realization. All that data must be stored.

A single digital mammogram can exceed 30 MB. A CT chest study can create 140 images in less that 20 seconds, amounting to 73 MB of data. Biplane rotational angiography machines using image intensifiers are able to create between eight and 32 images per tube rotation, easily generating 500 MB per study. The capability exists for some ultrasound units to capture cine loops, which generate 24 MB of data every second from 30-image loops.

One answer may be found in holographic memory, a new technology that could rescue radiology and other industries driven by ravenous appetites for data storage. The magnetic memories used in every computer are about to hit an impenetrable barrier governed by the laws of physics. The tiny magnetic crystals that store each bit of data cannot be made much smaller without subjecting data to destruction by ambient thermal energy. This physical limit on data density will soon be reached, and holographic storage is a leading replacement candidate.

Radiologists heard about one version of this technology at February's Medical Imaging meeting in San Diego. Michael E. Thomas of Colossal Storage in Fremont, CA, presented a paper on 3-D volume optical data storage, a ferroelectric holographic method said to be capable of storing 200 gigabits of data or more within a single square inch of optical media.

Thomas believes his technology may one day ease the burden on jukeboxes and redundant array of inexpensive disks (RAID) devices employed by hospitals to archive digital images.

"3-D volume holographic data storage will allow all digital images to be manipulated for real-time simulation, interpretation, data transmission for real-time consultation, and massive data archiving safe from degradation for years to come," he said.

Storage industry experts are skeptical. Jim Porter, president of DiskTrend, a storage industry research firm in Mountain View, CA, said holographic storage announcements are mostly smoke and no fire, that few offer realistic time lines for commercial availability and even fewer discuss specific products.

Thomas doesn't expect his first working prototype for two to three years after the first round of funding.