In neurosurgery, the extent of resection (EOR) is crucial, particularly in the management of malignant gliomas. These tumors are characterized by a diffuse infiltration into the surrounding brain parenchyma. Delineation between tumor and normal brain parenchyma can therefore often be challenging. In recent years, researchers and surgeons have developed and implemented various techniques to improve the visualization of tumors during surgery. This chapter explores current approaches to intraoperative imaging in brain tumor surgery, comprising conventional techniques such as neuronavigation, techniques using fluorescence guided surgery, and further highly precise developments such as targeted-fluorescence, Raman spectroscopy, and hyperspectral imaging. These innovative methods aim to enhance surgeons’ ability to identify and remove tumor tissue more effectively, potentially improving patient outcomes.