Laser-based imager determines severity of burns

A laser-based imaging system developed byAïmago (Lausanne, Switzerland) -- a startup in the science park at École Polytechnique Fédérale de Lausanne (EPFL; Lausanne, Switzerland) -- shows how blood circulates in bodily tissue. Its developers believe that it could be used to facilitate the work of burn specialists and plastic and reconstructive surgeons.

Physicians look at blood circulation to judge the extent and severity of a burn. On the screen of the EasyLDI device -- which was invented in EPFL’s Biomedical Optics Laboratory -- the blood circulation in the tissue is displayed in real time. Color variations in the images reveal differences in the intensity of the blood circulating over a volume of skin around 50 cm² in area and 1-2 mm deep.

The system exploits the use of Laser Doppler Flowmetry (LDF), a technique that has already proven reliable in evaluating wound depth. But while existing machines are bulky and complicated to use, the new system is claimed to be much smaller and lighter.

In the EasyLDI system, a laser beam is directed at the skin surface where it is reflected by red blood cells and static tissue. Light reflected off stationary tissue undergoes noDoppler shift while light reflected off moving red blood cells does. The degree of Doppler shift is proportional to the velocity of the blood. The light is reflected back out of the tissue and onto a detector developed in the Biomedical Optics Laboratory that can capture 20,000 images per second. From that data, the average speed of the blood in the tissue can be calculated.

In late August 2011, EPFL professor Theo Lasser and Michael Friedrich from Aïmago were named the winners of the 2011 CTI Swiss MedTech Award and awarded 10,000 Swiss francs for their efforts developing the system.

-- Posted byVision Systems Design