G.V. Zenkovskiy, A.A. Kornilova, V.M. Naskhletashvili

Photodynamic therapy (PDT) is one of the most progressive and widely used diagnostics and cancer treatment methods all over the world. This work describes PDT method implementation for prostate cancer. The method-s gist is the oncology tissue irradiation with low intensity laser emission, which doesn-t cause normal tissue thermal necrosis. The special dye called - photosensitizer (PS) ? with absorption maximum on irradiation wavelength introduced into the tissue before irradiation process. PS gets the sufficient energy after irradiation to activate cell oxygen. These leads to the cancer tumor photo destruction process activation. The active oxygen distracts tumor cell membranes and acts locally. Actually, tumor tissues get more laser emission energy then normal tissues, this leads to selective destruction and limitations of metastatic process. In this work we determine physico-mathematical model that describes prostate cancer PDT process most thoroughly. We have set the computer model by determining prostate tissue optical properties and setting the bounds between prostate areas with different optical properties. Then we used diffuse approximation of transport equation to simulate light propagation in prostate tissues. To take into consideration PS properties we applied dose distribution equation witch depends on extinction coefficient, photobleaching velocity, total emission current through the tissue and initial PS tissue concentration. To introduce laser emission into the prostate tissue we used brachy therapy method, which includes the following steps: determining the prostate location by transrecatl ultra sound, preparing special needles sample according to prostate location, introducing hollow needles into the tissue and inside prostate by ultrasound control, introducing optical fiber into the tissue.