Drug quantification in turbid media by fluorescence imaging combined with light-absorption correction using white Monte Carlo simulations

Abstract

Photodynamic therapy (PDT) has been clinically accepted to treat certain types of malignant tumors as well as some nonmalignant diseases.^{1, 2} In PDT a photosensitizer (PS) is administrated either systemically or topically. It is activated by irradiating appropriate light to the sensitized tumor. As the PS absorbs light, the gained energy can be transferred to nearby oxygen molecules, leading to the formation of highly reactive oxygen radicals and thereafter tissue damage. PDT is a nonthermal photochemical reaction, which requires the presence of a photosensitizing agent (i.e., PS), oxygen and light, simultaneously. In PDT, quantification of the PS in a noninvasive way is in many cases a critical issue, since light dosimetry, irradiation parameters, and therapeutic outcome depends significantly on the PS quantities distributed in the region of interest (ROI).