الفهرس 
INTRODUCTION Aim of the workOnly 14 pages are availabe for public view
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Abstract
rdality with selective turnOUT destruction while sparing unaffected tissue. The ~otodynamic mechanism of action that leads to turnOUT destruction is based on the :rncrete interaction of light, ~ensitizer, and molecular oxygen. This modality is ~ying on the preferential localization of the photosenstizing drug in malignant bssues. The therapeutic efficacy of PDT using a systemically administered Photofrin@ has been demonstrated in animal models and clinical trials. A drawback of this agent is a generalized skin photosensitivity that can last for 1-2 months. One approach taken to avoid this problem is the synthesis of photo sensitizers with short elimination half-lives (e.g. meso-tetrahydrxyphenyl-cWorin), which appear to have less persistent cutaneous photosensitivity. Other studies have explored the effectiveness of local photosensitizer administration via intratumoral or topical routs. The most recent and novel technique is the induction of endogenous porphyrins through the exogenous administration of its natural precursor 5- aminolevulinic acid (ALA) either topical or less frequently systemic. ~ We investigated this new modality in the treatment of superficial turnoUTS in : different anatomical sites and for different pathologies including basal cell carcinoma, squamous cell carcinoma and transitional cell carcinoma. The aim was to prove effectiveness of this new modality in control of such turnOUTS. Moreover, we investigated the new technique of photosensitization using the local application of 5-aminolevulinic acid for photodynamic therapy in skin and bladder cancers. Furthermore, we have investigated one of the second generation photosensitizers that is meso-tetra (hydroxyphenyl)-cWorin (m- THPC) in photodynamic treatment of cancer lip.