A cardiac nuclear scan is an imaging procedure in which a small amount of radioactive material is injected into a vein and a special camera records the movement and uptake of the radiotracer within the heart. The resulting images provide information about the coronary arteries and heart function.
There are three common types of nuclear heart scans: the myocardial infarction scan, myocardial perfusion scan, and multigated-acquisition (MUGA) scan. Each of these procedures uses a different radiotracer.
The two main types of nuclear heart scans are single photon emission computed tomography (SPECT) and cardiac positron emission tomography (PET). The SPECT used to diagnose coronary heart disease (CHD). Combining SPECT with a stress test can show problems with blood flow to the heart and the areas of damaged or dead heart muscle tissue. SPECT also can show how well the left ventricle pumps blood to the body. PET used for the same purposes as SPECT. Compared with SPECT, PET takes a clearer picture through thick layers of tissue. PET uses different tracers than SPECT.
The main positives of SPECT are that it is much more available and widely used and much cheaper than PET in terms of purchasing equipment and radio tracers. SPECT radio tracers also have half-lives of up to six hours, allowing a lot of imaging time, while PET tracers only have a half-life of about 75 seconds.
Right now, however, there is no clear advantage of using one scan over the other in all situations. Research into advances in both SPECT and PET is ongoing.