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(Continued from page 134)
dependent upon concentration, pH and temperature. Valleys in spectra indicate attenuation peaks (13).
The fluorescence emission of Phe 282, Tyr 303 and Trp 348 (330,350), (360 Alfano). Most proteins fluoresce maximally between 308 and 350 nm (24) NADH & NADPH 465, 4-pyridoxic acid 430, pyridoxic acid lactone 440, pyridoxal 5' phosphate 520/385, elastin 420/510/520, collagen 395/390, hematopophyrin 610/675, flavin mononucleotide & dinucleotide 515/520.
Knowing the tumor and normal brain tissue absorption and fluorescence spectrum can be used in the operating suite to both better delineate the tissue and to remove the neoplasm. Using a narrow bandwidth filter, which allows maximal light transmission at the specific tumor luminescence and a broader filter which would allow less transmission in the range of tumor increased fluorescence would identify the tumor only. This can be accomplished by wearing fitted lenses. Having specific delineation of the tumor margins would improve resection and outcome.
The manufacturing of the appropriate lens for the observation would have a transmittance/density absorption curve based upon the data in figure 4.
On the other hand, utilizing maximal tumor absorption in, areas where there is no normal tissue absorption allows the use of selective wave laser ablation. The laser light would be absorbed by the tumor tissue thereby destroying it but would not affect the surrounding normal brain.
(Continued on page 136)
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