5-ALA

5-ALA is a drug that is used to stain tumor cells. Patients receive this drug 4–6 hours before the operation. It is then traveling to the brain and is processed in the cells of the nervous system. Especially the malignant forms of gliomas (glioblastomas) are not able to process 5-ALA like the rest of the healthy brain, which is why a not completely processed form of 5-ALA is accumulating in glioblastoma cells. This particular form of 5-ALA can be brought to pink fluorescence after stimulation with blue light. During the operation the surgeon can switch the microscope to the blue light mode and search for pink fluorescence to distinguish healthy brain tissue from the tumor. However, 5-ALA is only staining the malignant forms of gliomas and does not work in low grade gliomas. Therefore it only helps to visualize certains types of brain tumors.