Glioblastoma multiforme (GBM) and anaplastic astrocytoma (AA) are the most common primary malignant brain tumors. Survival of patients with these brain tumors is directly related to the extent of resection. Consequently, a great deal of effort has been directed at developing techniques and technologies that allow more extensive, safe resections. This study will test a loupe-based wearable device in the clinical setting and compare its accuracy with a large operative microscope to identify tumor tissues. Postoperative histopathological analysis on tumor tissues will be used as gold standards for comparison. The outcome from this study will be a low-cost, miniaturized, easy-to-operate, loupe-based fluorescence imaging device for intraoperative guidance of brain tumor resection with the same level of accuracy as the large microscope.