Like many nuclear medicine procedures, cardiac molecular imaging
involves the injection of a radioactive label, or
"radiotracer", which circulates into the heart. Using either
a PET (positron emission tomography) or SPECT (single photon emission
computed tomography) scanner, the patient then undergoes a scan of the
heart that detects the radioactive signal from the heart and produces
a detailed three-dimensional image.
How does nuclear imaging help people with heart disease?
A nuclear medicine physician can then determine the amount of blood
flow (perfusion) that the walls of the heart are receiving, whether
the cells in the heart are functional and healthy (viability), and
whether the heart has suffered permanent damage from a prior heart
attack (myocardial infarction).
When evaluating the blood flow (perfusion) to a patient’s heart, it
is very useful to evaluate the blood flow while the heart is working
faster and harder (under "stress") and compare the blood
flow to when the heart is beating normally (at "rest"). When
evaluating the functional (viability) status of the heart, it is not
necessary to test the heart under stress.