A Multi-Led Source for Photoradiation Therapy
Light sources emitting at the long wavelength wing of the absorption spectrum of Hematoporphyrin (Hp), between 610 and 640 nm, are currently used in photoradiation therapy (PRT) in order to maximize penetration of light into the tumor mass. Optical output powers of several watts are necessary to ensure the suitable irradiance (30÷100 mW/cm2) at the tumor surface. Filtered high-power Xenon or halogen lamps, and ion-laser-pumped dye lasers tuned at λp ≃ 630 nm are the most common sources used so far. The overall electrical-to-optical conversion efficiency of these sources is quite small, typically 0.05% (0.2 for halogen lamps). Flash-lamp-pumped dye lasers are now commercially available at average output power of 10÷ ÷20 W; the efficiency is ~ 0.8% in the red 1. Their use for photo-dynamic therapy is under investigation 2. Gold vapor lasers emitting l÷6 W at 628 nm with 0.2% efficiency represent another interesting new source for PRT of tumors 3.
KeywordsHuman Serum Albumin Average Output Power Superficial Tumor Diode Laser Array Wavelength Wing
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