Using a spectrophotometer equipped with an internal integrating sphere
, the absorption (mu a) and the reduced scattering (mu s') coefficient
s of ex vivo human colon tissues were evaluated from reflectance and t
ransmittance measurements. mu a and mu-s' varied from 47.7 to 1.0 cm(-
1) and from 14.2 to 6.2 cm(-1), respectively, on passing from 300 nm t
o 800 nm. These results can be used to estimate the optical penetratio
n depths when photodynamic therapy or light-induced fluorescence proce
dures are used. (C) 1994 Wiley-Liss, Inc.