We offer on-site nuclear stress testing for cardiac evaluation to detect atherosclerosis in its earliest stages and to prevent its progression. Myocardial Perfusion (nuclear stress test). In addition to EKG monitoring a radioisotope is injected before and immediately after exercise in order to monitor blood flow to the heart. The radioisotope allows images of the heart to be obtained right before and after exercise that will show whether blood flow to the heart is normal.