A non-invasive, three-dimensional, diagnostic laser imaging system for accurate wound analysis

A PC-based laser imaging system has been developed that can accurately image and analyse three-dimensional (3D) surfaces in healing wound tissue. The device consists of a laser diode and sensor mounted to a motorized, bi-directional, X-Y table. The laser measures the distance to the wound surface as the X-Y table moves over the wound. The laser beam diameter is 1 x 2 mm and can measure distances as small as 8 microns. The distance information from the laser is used to produce the 3D image and to calculate the volume of the wound. The accuracy of this device is demonstrated by measuring rubber model wounds of 0.5, 1 and 2 ml. The per cent error for the 0.5 and 1 ml model wounds was less than 1 per cent and approximately 4 per cent for the 2 ml model. Studies were done in which full-thickness wounds were made on rats and monitored over a two week period. The rats were scanned five times during this period and the wound area and volumes calculated. The laser measurements are compared to measurements using saline and wound thickness multiplied by wound area.