Portable Laser Doppler Flowmetry in Studying the Effect of Diabetes Mellitus on Cutaneous Microcirculation
Microcirculatory blood flow can be measured using laser Doppler flowmetry(LDF). However, the size and weight of the currently used system can be improved to make it light and portable. This paper describes a portable laser Doppler flowmetry(pLDF)system for taking real-time blood flow measurements in the dorsal foot of a diabetic. The system is comprised of a miniaturized probe, a fast digital signal processing(DSP) unit. The probe comprises an IR laser diode to illuminate tissue through an optical fiber and a photodetector, positioned 1 mm from the laser spot. The DSP uses the FFT based algorithm to estimate the laser Doppler power spectrum density. The pLDF unit is applied to the clinical evaluation of diabetes mellitus and a very high correlation was observed to exist between relative flow capacity(RFC) and occurrence of ulcer.