A nuclear stress test is a common procedure for evaluating how well blood is flowing to and through your heart during different levels of activity. Patients with unexplained chest pain, shortness of breath or high risk factors for coronary artery disease may be candidates for this test. After a radioactive contrast dye has been injected intravenously and allowed time to circulate to the patient’s heart, small disks called electrodes are attached to the chest, arms and legs so that an electrocardiogram (EKG) can be administered. Patients who are able to exercise will then do so on a treadmill in order to increase their heart rate to a certain designated target or until uncomfortable symptoms such as dizziness or chest pain make it necessary to stop. Patients who can’t walk on a treadmill can be administered medications to elevate their heart rate. After exercising or the provision of the medication, additional dye is injected into the patient and X-ray images are taken of the heart. These images are compared to those taken while the patient was at rest.