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Interactive exhibits

Just as the curtain was about to fall on LASER 2007, I found what gets my vote for the most interactive exhibit of the show. Michelson Diagnostics, a UK-based start-up founded in early 2006, was demonstrating its benchtop optical coherence tomography (OCT) scanner and displaying real-time sub-surface images of everything from strawberries to the fingerprints of anyone who stopped at the booth (including me).

OCT works by focusing laser light onto a tissue surface and using an interferometer to mix the reflected light from below the surface with the original light source. The interferometer only detects light that has not been scattered and builds up a picture of the structures below the surface. OCT works to a depth of around 2 mm, after which all returning light will have been scattered at least once.

Gordon McKenzie, the company’s applications director, talked me through some of the key features of the turnkey EX-1301 OCT microscope. “We use a swept laser source that continuously scans through a wavelength range from 1260 to 1360 nm,” he said. “We scan at 10 kHz and this gives an axial optical resolution of less than 10 microns (in tissue) and a lateral optical resolution of 10 microns.”

The company’s key strength is in the design of the Michelson interferometer. It projects laser light to four different depths to build up the sub-surface image. The images that are displayed on the screen are raw images that have not been processed or enhanced in any way.

McKenzie told me that the company is working with two hospitals in the UK who are using prototype devices to study excised human cancer tissue. One of the hospitals is looking at cervical and oesophageal cancer tissue while the second is concentrating on skin, lung and oral cancers.

And now to the fun bit — seeing a cross-section of your fingerprint. After looking at my middle finger, McKenzie told me that I have “the most worn fingerprint of anyone we’ve ever scanned”.

I’ve attached my fingerprint image and a “typical” image to this post so you can make your own mind up. You can see the top epidermal layer and the spiral structures are sweat glands. Also note that the top of surface of my finger is decidedly flat compared with the ridges of typical fingerprint. Must be all this blogging from LASER!

Posted by Jacqueline Hewett on June 22, 2007 11:43 AM | Permalink