Fluorescence-guided resection using 5-ALA induced tumor fluorescence of malignant gliomas allows for better identification of tumor tissue and more radical resection in select patients and improvements in progression-free and overall survival. With new developments in surgical microscopy, the development of digital exoscopes have provided advanced visualization as well as improvements in ergonomics and accessibility of the surgical field. The use of the exoscope in 5-ALA fluorescence-guided tumor surgery has the potential to enhance the ability of the surgeon to remove brain tumors with high efficacy. While algorithms for use of 5-ALA fluorescence have been optimized for use with traditional microscopes, the use of fluorescence techniques in newer digital exoscopes have not been developed. The primary outcome of the study is to obtain parameters to optimize visualization of fluorescence intensity and perform optimization based on the intensities achieved. The operating ORBEYE exoscope will be fitted with a blue light filter. All experiments will be performed in darkened operating rooms. The ORBEYE exoscope will be set up at constant distances from the target and incident light intensities. The focal distance and light intensity settings will be recorded from the data displayed on the microscope. Patients (experimental group) will receive 5ALA treatment before operation, blue light filter imagining will take place after tacking up dura and prior to direct resection. The expected outcomes of image analysis will be to have a set of exoscope parameters optimized for visualization of 5ALA tissue in different tumor types. This 5ALA characterization of visualization parameters has never been completed on an exoscope. Optimizing ORBEYE exoscope parameters will define a standard in glioma resection using 5ALA under a novel exoscopic filter as well as contribute insight into the use of the fluorescent filter for additional tumor types.

Inclusion Criteria:

• Male and female ≥ 18 years of age
• Must have a suspected or biopsy-proven glioma (World Health Organization grade II or IV), new or recurrent
• Indication for craniotomy for removal of a suspected or recurrent brain tumor
• Karnofsky Performance Scale ≥ 60%
• Willing and able to provide informed consent or have surrogate consent by legally authorized representative

Exclusion Criteria:

• Male and female < 18 years of age
• Porphyria, hypersensitivity to porphyrins
• Renal insufficiency as defined by a creatinine > 2.0 mg/dL
• Hepatic insufficiency as diagnosed in preoperative medical clearance evaluation
• Females of childbearing potential with a positive pregnancy test
• Nursing women
• Unwilling or unable to provide informed consent