Neurosurgeons usually work regular office hours in a hospital or private clinic. Theywork 9 to 4 and through lunch to accommodate some of their patients. Some neurosurgeons are also affiliated with universities and may teach or conduct research. There are many different tools available to a neurosurgeon. An MRI is a scanning device that uses a magnetic field, radio waves and a computer. MRI stands for magnetic resonance imaging. Signals emitted by normal and diseased tissue during the scan are assembled into an image that can show the surgeon what the problem is and where it is located. A CT or a CAT scan stands for computerized axial tomography. This refers to an X-ray device linked to a computer that produces an image of a predetermined cross-section of the brain. A special dye material may be injected into one of the patient's veins prior to the scan to help make any abnormal tissue more evident. Neurosurgeons must prepare themselves for the chance that they will lose a patient.