Liquid crystal thermography in the diagnosis of scaphoid fractures.

LCT consists of pliable latex sheets impregnated with cholestrol crystals which respond to different temperatures by emitting different wavelengths of light ranging from brown (cool) through yellow and green to blue (hot). These latex sheets form one wall of a sealed box with the opposite wall being made of perspex to allow the thermographic image to be viewed. The thermographic detectors are calibrated to react to different temperatures. Each one has a mean temperature and responds 2°C above and below this mean. There are eight detectors which respond to mean temperatures of 24, 26, 28, 29, 30, 31, 32 and 33°C. Each box is airtight and has a valve through which air can be pumped to make the pliable latex sheet assume a convex contour which can be moulded around the subject under study. The box is held in a frame with a polaroid camera and a flash unit, thus a permanent picture of the thermographic image can be obtained (Novamedix Ltd, Whitchurch, England).