Development of a novel combined fluorescence and reflectance spectroscopy system for guiding high-grade glioma resections

Abstract: Total resection of glioblastoma multiform (GBM), the most common and aggressive malignant brain tumor, continues to be a challenge. Achieving complete resection is limited by difficulty in intraoperative discrimination between normal and residual tumor cells. This project contributes to the development and evaluation of a fiber-optical based fluorescence/reflectance spectroscopy system as an intraoperative guiding tool, using $\delta$-aminolevulinic acid (ALA)-induced Protoporphyrin IX (PpIX). The main aim is to combine the diagnostic potential of reflectance and fluorescence to improve clinical applicability. In this context, 5 LEDs coupled to a hand-held optical fiber was employed to deliver UV/visible light to the sample sequentially. Remitted light from the tissue; including diffuse reflected and fluorescence of endogenous and exogenous fluorophores, as well as its photobleaching product, is transmitted to one photodiode and four avalanche photodiodes. This instrument has been evaluated with very promising results by performing various tissue-equivalent phantom laboratory and clinical studies.