NXDC-MEN-301: Subjects are being asked to participate in this study because they have a brain tumor, a meningioma, and surgery is recommended to remove it. The sponsor of this clinical trial, NX Development Corp, has developed the study drug, Gleolan, an imaging agent that in some brain tumors, can make the tumors glow red-violet under a special blue light. This may make it easier for the study surgeon to identify the tumor and to remove it. As part of the study, subjects will drink the Gleolan before your surgery. The goal is to safely remove the tumor.