laser-Doppler, perfusion, blood flow, microcirculation, biophotonics
This paper reviews the development and use of laser-Doppler perfusion monitors and imagers over the past two decades. The enormous interest in microvascular blood perfusion coupled with the 'ease of use' of the technique has led to 1500+ publications citing its use. However, useful results can only be achieved with an understanding of the basic principles of the instrumentation and its application in the various clinical disciplines. The basic theoretical background is explored and definitions of blood perfusion and laser-Doppler perfusion are established. The calibration method is then described together with potential routes to standardisation. A guide to the limitations in application of the technique gives the user a clear indication of what can be achieved in new studies as well as possible inadequacy in some published investigations.