The challenge for nuclear cardiology is to demonstrate that it can provide more information than competitive modalities at comparable or lower cost. In considering patients for nuclear cardiology procedures, presentations can be divided into 9 subsets: within each subset, nuclear cardiology tests should be employed where incremental information is provided over the information available without performing the test. (1) Patients with no known coronary artery disease (CAD); for diagnosis, nuclear imaging is useful in patients with intermediate probability of CAD. For prognosis, assessment is based on extent of ischemia, where we have shown that nuclear testing provides incremental information, especially in patients with a high likelihood of CAD, such as those with typical angina. In the remaining categories (2-9), nuclear cardiology studies are predominantly used for purposes of risk stratification. Here the greatest value is in patients deemed to be at intermediate risk before nuclear testing. (2) Postmyocardial infarction: stress nuclear imaging provides an alternative to angiography for risk assessment of clinically uncomplicated patients. (3) Poor ventricular function: Nuclear testing is particularly useful for differentiating patients with hibernating myocardium (the defect is reversible), with stunned myocardium (no defect is present), or with myocardial infarction (the defect is persistent). (4) Unstable angina: Following current federal guidelines, nuclear imaging in medically stabilized low-to-intermediate risk patients with unstable angina is likely to increase. (5) Postcatheterization patients: Nuclear imaging is useful when there is uncertainty regarding the choice of medical management or revascularization. (6) Pre-noncardiac surgery patients: Nuclear imaging is clearly helpful in patients with intermediate clinical risk and may provide useful information in clinically high-risk patients. (7) Post-PTCA patients: Due to the intermediate likelihood of restenosis, nuclear scans are frequently employed 2-6 months following intervention. (8) Post-CABG patients: We have demonstrated that exercise scintigraphy (SPECT) provides incremental prognostic information over clinical and exercise electrocardiographic results and is useful when clinical risk of events is considered intermediate. (9) Long-term management: Scintigraphy provides objective information regarding progression or regression of CAD.