The clinical evaluation of the use of computerized transaxial tomography in the diagnosis of brain tumors, especially as compared to nuclide brain scans but also as compared to angiography and pneumoencepalography. Specifically to try to define the capability of the scanner to predict earlier lesions, cystologic type, and ability to localize lesions. This study will also attempt to determine whether there is a clinical presentation for which the EMI or the nuclide brain scan is the preferable initial diagnostic imaging study, and for which angiography and/or pneumoenceptalography are also to be desired; to determine absorption data in normal patients.