To investigate the feasibility of non-traumatic detection of porphyrin for cancer diagnosis

optical property of human skin was studied by spectral analysis.The reflexion

transmission and fluorescence spectra of skin were taken using RF-5301PC spectrophotometer.The spectra suggest that

in the skin

there were mainly four kinds of illuminant substances——protein

carotenoid

NADH and melanin.The excitation and emission spectra of skin were taken to verify what affect of those illuminant substances might cause in porphyrin detection.The fluorescence at 360nm from the skin with excitation wavelength of 280nm was determined to be the result from protein.And at 350nm excitation

an emission spectrum around 452nm

similar to that from carotenoid sample

was observed.The observed fluorescence at 400nm and 460nm might result from the protein and NADH in the skin respectively.It was known from the literature that melanin had no emission at observed range

while oxidized melanin had fluorescence at 580nm

which was also observed from the fluore-scence spectra of the skin.No emissions

from those illuminant substances in the skin

were observed at the fluorescence wavelength of porphirin

625～630nm.It demonstrates that the illuminant substance of skin won’t affect the measurement of porphyrin.It was also clear

from the transmission spectra of skin

that the transmission window of skin is from 600nm to 900nm

which confirms the possibility of the non-traumatic detection of porphyrin.