System for determining the concentration and visualization of the spatial distribution of photosensitizers based on tetrapyrrole compounds in the tissues of the human ocular fundus

摘要

We developed a system for the analysis of the spatial distribution of photosensitizers (PS) based on tetrapyrrole compounds in the tissues of the retina. Tetrapyrrole compounds were chosen because the most of them are characterized by strong absorption in the tissue transparency window. Calibration curves for determining the concentration of PS by different methods were constructed. Registration system of PS's fluorescence consists of two optical channels. First channel based on single point spectroscopic technique is used to determine exact concentration of PS at a certain point of the field. Second channel based on imaging sensor is used for concentration mapping in whole field of view. The joint use of these two methods allows determining the concentration of PS in different points of the field quickly and accurately, which provides the exact determination of tissues in pathologic condition and informed choice of irradiation dose for photodynamic therapy.