We have evaluated the utility of a single-photon axial tomographic scanner (ECT) in brain imaging, using routine tracers in 238 patients. When compared with routine delayed gamma-camera images (DGCI), there was agreement in 191 negative studies and 39 positive studies. Four patients had positive DGCI and negative ECT studies, and four had positive ECT and negative DGCI. In the 102 patients in this series who also had transmission CT (TCT) studies, there were five who had positive emission studies and negative TCT, and 38 with an abnormal TCT and normal ECT. The ECT was occasionally helpful in distinguishing brain and skull metastases, in better portrayal of deep lesions, and in resolving equivocal DGCI findings. For the ECT to become clinically rewarding, however, we feel that it will need development of new tracers that will provide functional information in addition to that already attainable by routine gamma-camera images.