The objective of this study was to test the clinical practicability of a 3D-cardiac-positron emission tomography(PET) procedure. During preoperative viability diagnostics of the myocardium with fluorine-18-fluorodeoxyglucose(18F-FDG)PET, comparative recordings were made in 2D (ECAT Exact) and 3D Mode (Quest). Ten patients (2 women, 8 men, ages 34-72 years) with coronary artery disease and a known myocardial infarction in the history were examined. Both examinations were made on the same day following single FDG injection. In 9 of the 10 cases, 3 independent examiners arrived at the same diagnoses from the 2D and 3D recordings, whereby only one-third the activity used for 2D exposures was required for 3D acquisition. In one case, the 3D recording showed no accumulation around the anterior wall near the apex, in spite of demonstrated, albeit limited, viability in the 2D mode. The cause of this discrepant finding is assumed to lie in equipment/uptake and patient-related differences in the test configuration. In summary, 3D acquisition offers a promising alternative to 2D recordings in the viability diagnostics of the myocardium based on a considerable reduction in radiation exposure for patients and personnel, as well as reduction in the costs for radiopharmaceuticals. Further evaluation of the method in broader studies would appear necessary.