Local Spectrum measurement system for 5-Aminolaevulinic acid Induced Protoporphyrin IX fluorescence

We have developed a local spectrum measurement system for 5-Aminolaevulinic acid (5-ALA) induced Protoporphyrin IX (PpIX) fluorescence, which consists of a semiconductor LASER, a CCD spectrometer, a personal computer and a fluorescence measurement probe. Performance evaluation results showed that the probe has sufficient ability to measure PpIX fluorescence with a spatial resolution of about 0.8mm around the working-distance. We used this probe for measurement of resected brain tissues to evaluate discrimination ability of 5-ALA induced PpIX fluorescence. To compare spectrums with pathology, we used a tissue holder to freeze tissues keeping their shape. This procedure enables precise comparison each measured point with pathology. Thirteen samples of brain tissue were measured using the developed system, and the results showed that PpIX fluorescence could be detected in tumor lesion even less than 1mm in diameter. Although some samples shrank to about 80% of holder size, characterized shape enabled to compare spectrums with pathology.