Computerized cranial tomography (CCT) and radionuclide imaging (RI) of the brain are both accurate techniques for detecting intracranial mass lesions. CCT is superior in detecting low-grade gliomas, cystic lesions, parasellar tumors, and brain stem lesions. Overall, CCT detection rates are slightly higher than those with RI, but the use of iodinated contrast media with CCT increases the risk of this examination. There is a significant difference in the generally binary (positive/negative) type of information offered by RI and the more specific information offered by CCT about the pathologic nature of a lesion and its precise location. In the evaluation of patients with suspected intracranial mass lesions, CCT is generally the preferable initial diagnostic test. However, RI may still serve as a satisfactory screening examination in certain well-defined clinical situations.