Mechanism of action<unk>  has activity very similar to that of a potassium ion (K+). Once in the myocardium, it is an active participant in the sodium-potassium exchange pump of cells. It is rapidly extracted by the myocardium proportional to blood flow. Its radioactivity is increased in viable myocardial cells reflecting cellular retention, while the tracer is cleared rapidly from necrotic or infarcted tissue. Pharmacodynamics When tested clinically,<unk>  is seen in the myocardium within the first minute of intravenous injection. When the myocardium is affected with ischemia or infarction, they will be visualized between 2–7 minutes. These affected areas will be shown as photon deficient on the PET scan.<unk>  passes through the entire body on the first pass of circulation and has visible uptake in organs such as the kidney, liver, spleen and lung. This is due to the high vascularity of those organs.
Rubidium-82
Prussian blue 
Dotinurad
Nickel tetracarbonyl
SeHCAT
Phenylsilatrane
Helothermine
Selenium disulfide