A nuclear stress test measures the distribution of blood flow to your heart at rest and during phyiscal activities . This is accomplished either byinjecting a radioactive dye to your blood stream and capturing the distribution pattern of the radioactive substance in your heart muscle during rest condition and physical activities like walking on a trade mill or by drugs , when an individual incapable of doing phyical activities. A gamma camera, captures the blood flow distribution in normal and affected heart muscle area, Images of blood flow distribution is captured during rest and activities and compared for any significant improvment in blood supply or persistent deficient or no blood supply to the affected muscle. You may be given a nuclear stress test, by your treating doctor in various suspected heart artery blockages, guantify hearts pumping function and many other heart realated ailments.