Red-IR Diode Laser for Combined PDT and Laser Hyperthermia

The objective of Phase I is to establish the feasibility of building and utilizing a diode laser-based instrument for combined photodynamic therapy (PDT) and laser hyperthermia treatment of malignant tumors. Use of PDT in conjunction with laser hyperthermia to treat cancerous tissue offers potential advantages over PDT alone. The proposed diode laser instrument would provide optical power at two different wavelengths (separately or simulataneously), one in the red (690 nm) for PDT and the other in the near-infrared (~800 nm) for laser hyperthermia. The instrument would incorporate two monolithic, independent, linear arrays of high efficiency, state-of-the-art, strained-layer, quantum well lasers each coupled to a common fiber-optic delivery system. Unlike present commercially available argon-pumped dye lasers, which are extremely large, inefficient, and expensive, the proposed laser system will be sufficiently small, portable, and cost-effective to permit easy installation and operation in hospitals and clinics. The prototype instrument will be evaluated by conducting combined PDT and laser hyperthermia on mouse tumors at the Massachusetts General Hospital's Wellman Laboratories of Photomedicine. Anticipated Benefits: Successful Phase I and Phase II programs would lead to commercialization of a highly versatile instrument for either separate or combined photo-dynamic therapy and laser hyperthermia treatments. The envisioned diode-laser-based system would be extremely compact and portable, and could be sold profitably at a fraction of the cost of existing laser systems with similar treatement capability.