Photodynamic therapy procedure

Photodynamic therapy uses non-thermal red light to activate verteporfin, which produces reactive oxygen species that locally damage the neovascular endothelium.24 Verteporfin treatment reduces the risk of loss of visual acuity and legal blindness over 1 to 2 years. Long-term results are not yet available. Severe photosensitivity for 3 to 5 days after the procedure is common and some patients experience a severe loss of vision. Eventually, most patients have some visual recovery. This procedure requires multiple treatments over time.22... 

Photodynamic therapy seems to offer broad applicability as either an adjunct to other endovascular procedures or as a means to treat de novo disease. At this juncture enough is known to imagine its potential without yet knowing its limitations. PDT could be an exciting tool for the emerging specialty of endovascular therapy, with potential applications in the heart, peripheral arteries, saphenous vein grafts, and arteriovenous grafts. 

Photodynamic therapy is a powerful medical procedure that exploits the combined action of light and a photosensitizing agent for the destruction of abnormal tissues. Ideally, the photosensitizer should accumulate in the tumor cells, and the photoactivation should be carried out by irradiation with innocuous red or near-infrared (NIR) light (photodynamic window = 650-1000 nm) in order to promote the photodynamic effects only at the injured areas. Because of their suitable photochemical and photophysical properties, porphyrins and mthe-nium-polypyridine complexes are potentially useful photosensitizers for application in photodynamic therapy (217-222). 

Choroidal neovascularization associated with age-related macular degeneration is difficult to treat with conventional laser procedures because normal retinal tissues can be destroyed, which results in loss of central vision. Photodynamic therapy offers the opportimity to selectively eradicate neovascular membranes while producing minimal damage to normal retinal and choroidal tissues. 

Photodynamic therapy appears to be a safe procedure. Infrequent complications include reactions at the injection site, transient reduction in vision, and photosensitivity lasting less than 24 hours. No interactions between verteporfin and other medications have been reported. 

S. Schmidt, U. Wagner, P. Oehr, D. Krebs (1992). Clinical use of photodynamic therapy in gynecologic tumor patients-antibody-targeted photodynamic laser therapy as a new oncologic treatment procedure. Zentralbl GyndkoL, 114, 307-311. 

Photodynamic therapy (PDT), the photochemical procedure now being used for cancer treatment, was sueeessfully adapted to help in the fight against AIDS. A dye has been identified that can latch onto HIV and related viruses and knock them out when a light is shown on them. 

Guyon, L., et al., 2012. Development of a new illumination procedure for photodynamic therapy of the abdominal cavity. Journal of Biomedical Optics 17 (3), 038001. Available at http // www.ncbi.nlm.nih.gov/pubmed/22502582. 

Al-Kassas R, Donnelly RF, McCarron, PA (2009) Aminolevulinic acid-loaded Witepsol microparticles manufactured using a spray congealing procedure Implications for topical photodynamic therapy. Journal of Pharmacy and Pharmacology 61 1125-1135. 

The treatment of AK lesions commonly involves focal or multiple ablative procedures such as cryotherapy, laser, curettage/excision/shave biopsy, and chemical peel. Large area treatments include topical therapies (mainly using topical 5-fluorouracil (5-FU), imiqui-mod, or diclofenac 3% gel) and photodynamic therapy (PDT), which have demonstrated efficacy in the treatment of AK in evidence-based studies [8, 9],... 

In these procedures the distal tip can be a straight, bare fiber or coupled to various types of tips [8] (ball shaped, triangular shapes and others) which can focus the beam into the tissue spread it in a specific ways or even diffuse it into all directions, depending on the type of interaction with tissue needed. Usually, diffusing tips are used for light delivery in photodynamic therapy (PDT) procedures. 

Finally, the goal of multimodal therapy is of great importance, using combinations of therapeutic and imaging techniques. Procedures under current development include smart particles for combined imaging (MRl/optical) and photothermal therapy [122, 123], or combinations of phototherapy and photodynamic therapy [124]. 

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