Light Dose and Fluorescence Imaging Depth in Dual-Wavelength PDT: a Numerical Study for Various Photosensitizer Distributions in a Layered Biotissue

Dual-wavelength photodynamic therapy (PDT) in combination with fluoescence monitoring has great potential in medical applications, in particular, in the treatment of skin diseases. In this study we conducted numerical Monte Carlo experiments in a two-layer skin model to simulate the absorbed light dose distribution for PDT with chlorin-based photosensitizers as well as to estimate the fluorescence imaging depth depending on the probing radiation wavelength and the photosensitizer (PS) in-depth distribution. The obtained dependencies provide a detailed overview of the light absorption profile and fluorescence signal formation for different PS distribution in layered biotissues, and can be used in various fluorescence based light dosimetry techniques.