The two main types of nuclear heart scanning are single positron emission computed tomography (SPECT) and cardiac positron emission tomography (PET).
SPECT is the most well-established and widely used type, while PET is newer. There are specific reasons for using each, which are discussed below.
Single Positron Emission Computed Tomography
SPECT is the most common nuclear scanning test for diagnosing coronary heart disease (CHD). Combining SPECT with a stress test can show problems with blood flow to the heart that only can be detected when the heart is working hard and beating fast.
SPECT also is used to look for areas of damaged or dead heart muscle tissue. These areas may be the result of a previous heart attack or other cause.
SPECT also can show how well the heart's lower left chamber (left ventricle) pumps blood to the body. Weak pumping ability may be the result of a heart attack, heart failure, and other causes.
The most commonly used tracers in SPECT are called thallium-201, technetium-99m sestamibi (Cardiolite®), and technetium-99m tetrofosmin (Myoview™).
Positron Emission Tomography
PET uses different tracers than SPECT. PET can provide more detailed pictures of the heart. However, PET is newer and has some technical limits that make it less available than SPECT.
Research into advances in both SPECT and PET is ongoing. Right now, there's no clear cut advantage of using one over the other in all situations.
PET can be used for the same purposes as SPECT—to diagnose CHD, check for damaged or dead heart muscle tissue, and check the heart's pumping strength.
PET takes a clearer picture through thick layers of tissue (such as abdominal or breast tissue). PET also is better than SPECT at showing whether CHD is affecting more than one of your heart's blood vessels.
A PET scan also may be used if a SPECT scan doesn't produce good pictures.