Single-photon emission computed tomography (SPECT) for thallium-201 myocardial imaging with a rotating gamma camera was evaluated in comparison with planar imaging and seven-pinhole tomography (7P). Cardiac phantom studies indicated that defects 2 cm in diameter can be visualized by both tomographic methods, but the 7P method showed propagation of the image into nearby planes, with lower image contrast. In a clinical study of 47 patients with myocardial infarction, both sensitivity and specificity for the SPECT system were high (96 and 89%, respectively); the 7P system, on the other hand, showed good sensitivity (93%) but poor specificity (68%), while planar imaging performed conversely (75 against 89%). The overall accuracy was not significantly improved in the 7P method (planar: 81%, 7P: 83%, and SPECT: 94%). Our study indicates that SPECT, which can reconstruct reliable tomographic sections in either the transaxial, frontal, or sagittal planes, will result in a remarkable improvement in the clinical evaluation of ischemic heart disease.