Fig. 1. Schematic of flow-mediated tissue fluorescence spectrum measurement system and end distribution of probe

Fig. 2. Calculated values of three filter criteria with different α and β pairs. (a) Variable coefficient of fluorescence intensity of tissue phantom; (b) linear correlation coefficient between fluorescence intensity with fluorescent component concentration; (c) difference distribution of fluorescence spectrum curve shapes

Fig. 3. Relationship between concentration of fluorescent components and fluorescence intensity before and after recovery. (a) Relationship between concentration of fluorescent components and fluorescence intensity before recovery; (b) relationship between concentration of fluorescent components and fluorescence intensity after recovery; (c) fluorescence spectrum curves of phantom before and after recovery. Among them, curve 1 is the normalized mean spectral curve of fluorescence spectra of five different concentrations of NADH tissue without absorption and scattering characteristics, curve 2 is the normalized mean spectral curve of fluorescence spectra of 45 groups of NADH tissue with different absorption and scattering characteristics after spectral recovery, and curve 3 is the measured normalized mean spectral curve of fluorescence spectra of 45 groups of NADH tissue with different absorption and scattering characteristics

Fig. 4. Changes of blood hemoglobin concentration and oxygen saturation during oxygen consumption. (a) Change of blood hemoglobin concentration; (b) change of oxygen saturation

Fig. 5. Changes of NADH fluorescence intensity of blood phantom before and after recovery

Fig. 6. Changes of normalized fluorescence intensity of the subject’s skin before and after recovery in the blood flow mediated process. (a) Normalized fluorescence intensity of skin before recovery; (b)normalized fluorescence intensity of skin after recovery

Table 1. Fluorescence response value and change rate of brachial artery occlusion and recovery in 4 subjects before and after recovery%