| 摘要 |
A method for monitoring the presence of selected chromophores in a sample of epithelial tissue, independent of the amount of a predetermined chromophore, the method comprising: illuminating an area of tissue by projecting light from a light source of at least two different wavelengths lambda<SUB>1</SUB>, lambda<SUB>2</SUB>; receiving light remitted by the illuminated area of tissue at a photoreceptor; analysing the received light to identify and measure the proportion of light of each wavelength remitted from the tissue I<SUB>r </SUB>(lambda); calculating the ratio of light at each wavelength returned from the tissue R<SUB>t</SUB>, (lambda), and then calculating Z=Formula (I); where 1 is chosen such that Z is independent of the amount of predetermined chromophore. Typically 1 is calculated such that Z=Formula (II); where j and k are such that 2j alpha(lambda<SUB>1</SUB>)=2kj alpha(lambda<SUB>2</SUB>)=1 where alpha(lambda<SUB>1</SUB>) and alpha(lambda<SUB>2</SUB>) are the absorbtion coefficients for the predetermined chromophore at each wavelength. |
