What type of isotopes is primarily used for cardiac imaging in PET scans?

Rubidium is primarily used for cardiac imaging in PET scans due to its unique properties that allow it to mimic potassium, an essential element for myocardial cells. This characteristic enables rubidium-based radiopharmaceuticals, such as Rubidium-82, to be absorbed by cardiac tissue, allowing for accurate assessment of blood flow and myocardial viability.

In the context of PET imaging, rubidium's short half-life and positron-emitting properties make it particularly suitable for capturing detailed images of the heart in real-time. This application helps in diagnosing conditions such as coronary artery disease and evaluating the overall health of the heart muscle.

Other isotopes listed have properties that do not align as closely with the requirements for effective cardiac imaging. While aluminium, magnesium, and iron have diagnostic applications in other areas of medicine, they are not typically utilized in the context of PET imaging for cardiac assessment.