Radionuclide Imaging (Nuclear Medicine)
Cardiac radionuclide imaging, primarily used for the patient with suspected myocardial ischemia or infarction, requires an intravenous injection of radioactively labeled compounds that have an affinity for the myocardium. These compounds localize within the myocardium in diseased or damaged areas, and a radioactivity detector such as a gamma camera can image their distribution. These tests are most commonly used in the evaluation of patients with angina and atypical chest pain (Figure 3-7). Gallium scans are occasionally used to assess for intrinsic myocardial disease such as myocardial sarcoidosis. Positron emission tomography (PET) with 18F-FDG (18F-fluorodeoxyglucose) is a problem-solving tool that has shown promise in assessing myocardial viability in pa-tients with known coronary artery disease and to assess for metabolically active infiltrative disease (Figure 3-8). In addi-tion, rubidium-82 and nitrogen-13 ammonia have been used as PET agents to evaluate myocardial perfusion.