An inexpensive light source for oncologic photodynamic therapy

A simple and inexpensive incoherent light source has been developed for use in photochemical diagnosis and therapy of several cancers. This source consists of a 400-W arc lamp filled with a special gas mixture that delivers a cold monochromatic beam at 630 nm wavelength after appropriate filtering through a bandpass interference filter. It delivers 70-150 mW/cm2 power, depending on the distance from the target. The light is concentrated with reflectors and focused at the window with properly aligned mirrors. The lamp housing is cooled by forced air distributed through appropriate vents. The dramatic effectiveness of the lamp is illustrated in a patient with an extensive extra-mammary Paget disease with eczematoid alterations.