Laser has clinical and security applications

A novel laser system that could help detect bone diseases is to be tested at the Royal National Orthopaedic Hospital.

The first commercially available laser of its kind, which also has potential uses in airport security, will be delivered to researchers at the hospital in Stanmore, where it will begin a four-year £1.7m programme funded by the EPSRC.

The spatially offset Raman spectroscopy (SORS) instrument uses a technique that allows it to scan deep into human tissue using simpler equipment than other spectroscopic lasers, making it more suitable for clinical use.

This means it can assess the chemical make-up of bones to look for illnesses such as osteogenesis imperfecta (brittle bone disease).

The instrument is also being studied as a bottle and packaging scanner for airport security and is already used to assess the content of drugs.

The STFC Central Laser Facility developed the laser for the project in collaboration with its spin-out firm Cobalt Light Systems and UCL’s Institute of Orthopaedics and Musculoskeletal Science.

‘SORS is really exciting because it gives us a potential screening system, where we look at not just a patient’s genes but how their bones are modified,’ Allen Goodship, the institute’s director and the project’s principal investigator, told The Engineer.

‘Most imaging gives you information on the mineral density [in bone], whereas Raman spectroscopy allows us to look at the chemistry of the bonds of the collagen and its interaction with the mineral.’

SORS works by detecting and analysing photons from the laser that spread out as they go deeper into a material. This removes the need to suppress the signal from photons reflected by the material surface that are stronger but do not spread out as much.

‘By gaining insight into the migration of photons, we realised they penetrate much deeper than we or anyone else thought possible,’ said Pavel Matousek, SORS’s inventor and chief scientific officer for Cobalt Light Systems.

‘On the basis of this effect, SORS enables you to do this with much simpler instrumentation. Rather than bulk instruments that occupy several rooms, you can do it with desktop equipment.’

To make the technique safe for use with human tissue, the laser has been adapted to shine a ring-shaped beam that can scan a wide surface area but has an intensity similar to that of a laser pointer.

The project will also look at using the laser to detect osteoarthritis, which causes joints to degrade, and osteoporosis, where bone mineral density is reduced, increasing the risk of fractures.

‘We may be able to convert the laser to an endoscopic device and look at the bone under cartilage,’ said Goodship.