Automatization of planning and control of photodynamic therapy of gastrointestinal organs

The main aspects of automatization of photodynamic therapy (PDT) planning include several key areas related to improving accuracy, efficiency and personalization of treatment. Mathematical modeling of light propagation makes it possible to calculate the distribution of light energy in biotissues taking into account their optical characteristics and pathology geometry. At the same time the use of optical diagnostic methods allows not only to plan but also to control in real time the photodynamic effect with parameters adjustment depending on the degree of photosensitizer photobleaching and the hemoglobin oxygen saturation, as well as to determine the optical properties of tissues exactly in the exposure area. These methods also make it possible to personalize the effect, since it is based not on a priori information about averaged properties of organs and tis- sues, but on dynamically changing and measurable parameters. The use of photodynamic therapy for tumor diseases of the gastrointestinal tract has shown effectiveness as an adjunct to surgical treatment, as well as for tumors of small size and as a method of palliative treatment. At the same time from the point of view of light propagation in tissues the walls of gastrointestinal tract organs represent rather complex multilayer structures, optical properties of which depend on physiological state and pathologies developing in the organ. These circumstances make the task of automation of planning of photodynamic therapy of GI organs urgent and nontrivial. In this paper we review the methods that solve this problem.