RecruitingPhase 2Drug trialDiagnostic Performance of Fluorescein as an Intraoperative Brain Tumor BiomarkerThis clinical research will evaluate the diagnostic potential of fluorescein as visualized through an operating microscope relative to 1) contrast enhancement on co-registered preoperative MR scans, 2) intraoperative ALA-induced PpIX fluorescence and 3) gold-standard histology obtained from biopsy sampling during the procedure. Subjects will include those people with operable brain tumor with first-time presumed pre-surgical diagnosis of high-grade glioma or low-grade glioma.