Metoda fotodynamiczna w diagnostyce i terapii guzów głowy i szyi

Abstract

The photodynamic phenomenon is based on the effect of tissue and cell fluorescence, which is excited by the light of a specified wavelength. Photodynamic diagnosing – PDD is based on the effect of ultraviolet rays on neoplastic and dysplastic tissues that emit light different from the healthy tissues. Tissue fluorescence spectrum can be obtained using fluorophoric substances that naturally occur in cells (autofluorescence) or applying photosensitizing substances before exposure (excited fluorescence – PDD). Fluorophores selectively accumulate in higher concentration in pathological than in normal tissues. An appropriate selection of the photosensitizer at an optimal dose, its high affinity to neoplastic cells with the best index of accumulation in the studied tissue seems essential for a good detection of lesions. In order to excite fuorescence, it is also necessary to provide energy using laser beams with the wavelength congruent with the absorption spectrum of the photosensitizer that has been accumulated in the neoplastic or dysplastic tissues. From all the presently available sources of light – lasers, which enable to obtain light with specifically defined parameters, have been applied most frequently. Photodynamic method as practical non invasive way was used in early diagnosis of precancerous lesion and cancer of skin and mucosa of oral cavity, bronchus, esophagus, large intestine, bladder and reproductive organ. Photodynamic therapy (PDT) is based on the cytotoxicity of light-activated photosensitizers accumulated in the cancer tissue PDT is minimally invasive treatment that uses light of a specific wavelength to activate a photosensitizing agent in the tumor and its microenvironment where pathological tissue is damaged. Photodynamic therapy proved effective to damage pathological tissue in cancer of skin and mucosa of oral cavity, bronchus, supper and upper part of digestive tract, bladder, vulva and uterine cervix. Small, last papers show ability of use photodynamic method to diagnosis and treatment head and neck cancer.