An experimental pilot study is proposed in order to determine the feasibility of an innovative approach to the generation, from a single solid-state laser source, of a multi-wavelength output with tunable- wavelength components suitable for simultaneous induction of laser hyperthermia and photodynamic therapy. The significance lies in the observation that the combination therapy has a higher success rate than the sum of the individual therapies. Secondly, the all solid-state nature of the system is superior, from an operational point of view, to the dye lasers currently being utilized for PDT. Finally, the ease of tunability over the .63-.69 micron range would make the system invaluable as a tool for clinical evaluation of the various classes of photosensitizers currently under consideration. It is likely that a medical device based upon the proposed mechanisms (OPO) would be used in conjunction with a laser system similar to the popular Laserscope KTP/532 or KTP/YAG lasers. The .532 microm output of these lasers is Q-switched with 20 w of average power. Here the conversion mechanism would be .532 microm to (OPO) to .63-.69 microm and then .532 microm to (OPO) to 1.064 microm. The feasibility study proposed herein involves the technically more difficult: 1.064 microm to (extra-cavity doubling) to .532 microm to .63-.69 microm. The difference in difficulties lies in the difference in frequency-doubling conversion efficiencies in the two cases. In the case to be examined here, less light will be available at .532 microm to initiate OPO process. If the proposed pilot study is successful, then it is very likely that a device will be developed for pumping directly with .532 microm light.
