Clinical application of photodynamic therapy (PDT) and fluorescence diagnosis is being extended in Russia. A. Tsyb MRRC scientists headed by Professor M. Kaplan have conducted experimental studies of the photosensitizers (PS): Photochem, Photosens, Photolon, Photoditazin, Radachlorin, Photoran, belonged to different classes, estimated their therapeutic effectiveness for malignant tumors of different histologic type. From the study of basic mechanisms of photochemical reactions with chlorine photosensitizers it became evident that the photosensitizers destroyed microciculatory bed, inhibited proliferation and tumor cells functional activity, induced apoptosis and necrosis at early stages of a tumor development. Effects of PS dosage and dose of light to be delivered to a target on a treatment outcome were studied. The results of experimental studies were used to support clinical application of focal, interstitial, systemic techniques with different PS as individual treatment modalities or as a modality combined with radiation therapy, surgery, chemotherapy, electrochemical lysis. Optimal PS and light exposure doses were determined, indications for the use of optimal PS and light doses for treatment of malignant neoplasms of the skin and the mucous membranes were formulated. Due to the use of high-tech effective treatment modalities developed in the Department of Fluorescence Diagnosis and Photodynamic Therapy of A. Tsyb Medical Radiological Research Centre – the branch of the Medical Research Radiological Centre thousands of patients have been cured. © 2022 National Medical Research Radiological Centre of the Ministry of Health of the Russian Federation. All rights reserved.