LASER DOPPLER VELOCIMETRY TO QUANTIFY UV‐B INDUCED INCREASE IN HUMAN SKIN BLOOD FLOW

Abstract— A laser Doppler velocimeter was used to quantify changes in cutaneous blood flow, in human subjects, after exposure to UV‐B radiation. Studies with three subjects showed a peak increase in flow at 6 h post‐irradiation. Dose‐response studies, on 8 subjects, at 24 h post‐irradiation showed that blood flow increased linearly with log UV‐B dose over a range of about 0.5 to 5 MED. Comparative studies with pigmented and non‐pigmented skins gave a quantitative measure of the photoprotective effect of melanin. The main advantage of the laser Doppler technique is that it allows easy quantification of a vascular response. However, there was no advantage when compared with detection of a visually determined threshold response, viz. a barely perceptible erythema.