This study aims to create an atlas based on the preliminary experience of the first feasibility study in neurosurgery. Hypothesis: That a confocal endomicroscope can be used during neurosurgery to provide in vivo histology that enables documentation of neurological pathology across a range of tumor ypes and grades, suitable for comparison with traditional histopathology from site-matched biopsies.

Confocal endomicroscopy is a medical imaging modality that allows real-time microscopy to be performed on living tissue in vivo. The procedure involves a small endoscope which is placed gently into contact with the tissue, providing significant in vivo magnification on a scale similar to that obtained by the pathology laboratory microscope. It is already in clinical use in the field of gastroenterological endoscopy, and investigational use in laparoscopy, dermatology and gynecology. Further, in recent pilot studies endomicroscopy has also been shown to be feasible in bronchoscopy, robot assisted prostatectomy and neurosurgery.The study will use both endomicroscopy and biopsy to document the histological appearance of a range of neurological tumour types and grades.

In subsequent analysis, the confocal image data and corresponding histology data and images will be used to document reliably observable features in the confocal images that are relevant to histopathology interpretation. Relevant images will be selected and discussed by comparison to frozen or permanent section histology for compilation into an atlas documenting comparison for the tumors seen in the study.

Inclusion Criteria:

• All patients with neurological pathology requiring surgery in which tumour resection might be evaluated by using biopsy

Exclusion Criteria:

• History of allergy to fluorescein
• Patients on beta-blockers or ACE inhibitors
• Pregnant women
• Inability to give informed consent