Measurement of the Penetration Depth in Biological Tissue for Different Optical Powers

In photodynamic therapy, the knowledge of the penetration depth for thelight is needed in order to ensure that the optical energy received by thetumorous tissue. In this study, the optical penetration depths of 635 nm laserlight in chicken breast tissue have been measured by using 8 tissue sampleswith different thicknesses between 2.5 mm and 9.0 mm. Transmitted lightintensities through the tissue samples have been measured with 11 differentoptical power values in the range of 130mW – 660mW. Measurement results foreach power value have been analyzed according to the Beer-Lambert law. With thehelp of statistical analyzes, it has been determined that the opticalpenetration depth of the light in biological tissue does not depend on itsoptical power.