Glioblastoma Multiforme (GBM) is an advanced stage astrosytoma originating from glial cells. The primary physiological feature that separates GBM from less advanced gliomas are microscopic projections that penetrate into the surrounding parenchyma. These microscopic "finger-like" projections are difficult to resolve using commercially available imaging techniques and are often missed during surgical resection. The incomplete surgical removal of these projections can lead to tumor re-occurrence and consequently a high mortality rate.

In order to increase the success rate of surgical resection, i.e. more complete removal, a novel spectroscopic technique known as non-resonant multiphoton photoacoustic spectroscopy (NMPPAS) is being developed in our laboratory. NMPPAS has shown the potential to differentiate cancerous from non-cancerous tissues based on endogenous chemical differences. In this technique a tunable, pulsed laser is used to optically excite endogenous biochemical species via a two-photon excitation event using radiation in the 700 nm and 1100 nm optical diagnostic window. Once the biochemical species have been optically excited, the resulting non-radiative relaxation is measured using a contact piezoelectric ultrasonic detector. Currently a NMPPAS fiber optic probe is being developed to transition this technique from the laboratory to animal studies and eventually clinical trials. This thesis will show the characterization and optimization of the necessary components of this NMPPAS probe; as well as, demonstrate this technique for the determination two-photon cross-sections. This cross-section work will aid in the deconvolution of the complex tissue spectra obtained during future tissue analysis.