Holography: Hyperbole or solution to PACS storage stress?

Imagine storing a year's worth of hospital imaging studies in a space no larger than a Rubik's Cube. It could happen once holographic storage technology hits the mainstream market.

Holographic storage - a potential low-cost, high-speed, high-volume solution - may answer the problem PACS administrators face: How to store the phenomenal number of digital images being generated by state-of-the-art imaging modalities?

Holographic storage could eventually affect PACS customers across the board by expanding storage capabilities exponentially, according to a recent paper (Radiol Manage 2006 May-Jun;28(3):38-46) that evaluates the potential advantages and disadvantages of holographic drive and storage technology.

"Current storage technologies are expensive to implement and quick to become obsolete," said John Colang, an Intel IT project manager.

Holographic drive technology offers hope for changing the current storage paradigm by presenting PACS administrators with a fast, affordable solution for the future, according to Colang.

Holographic storage, according to the Industrial Physicist, differs from current digital recording technologies in two fundamental ways:

• Holography enables massively parallel recording and reading of data rather than the serial approach of traditional methods. Instead of recording one bit of data at a time, holography allows a million bits to be written and read with a single flash of light.

• Holography exploits the entire thickness of a recording medium rather than just the surface. Instead of laying the data down on the surface of the medium like conventional digital recording, holography uses lasers and light to record data in 3D.

Potentially, holograms can store data at a volumetric density of one bit per cubic wavelength. Given a typical laser wavelength of about 500 nm, this corresponds to 1 terabit per cubic cm or more. Most hospitals require approximately 10 TB of storage for every 225,000 imaging studies performed.

Disadvantages include materials science deficiency issues that need to be addressed by manufacturers to ensure the stability of the storage medium itself. Colang expects these problems to be solved shortly by further research and prototype development.

The future may or may not be that far off. EE Times claimed in 2001 that holographic storage was nearing its debut, but five years later it has yet to appear.

Still, Colang cited indications that holographic storage devices may make their way into mainstream PACS deployment by 2010. PC Magazine reported in 2005 that optical storage technology firms had already demonstrated prototype drives that can store up to 300 GB on a single disc with a 160 MB/sec transfer rate.