Which tracer is primarily excreted via the hepatobiliary system?

The tracer that is primarily excreted via the hepatobiliary system is 99mTc sestamibi. This radiopharmaceutical is utilized in various imaging studies, especially in evaluating cardiac perfusion and certain types of tumors. Its mechanism of action involves uptake into the mitochondria of cells, which correlates with blood flow and cellular viability.

One of the notable characteristics of 99mTc sestamibi is its hepatic uptake. After being administered, it can enter the hepatobiliary pathway, leading to excretion in the bile. This property is particularly useful in certain diagnostic applications, as it allows for visualization of liver function and the biliary system.

In contrast to 99mTc sestamibi, other tracers listed have different excretion pathways. For instance, 99mTc pyrophosphate is often excreted by the kidneys and is used primarily for bone imaging. Similarly, 99mTc exametazime and 99mTc medronate are also predominantly renally excreted and are utilized mainly for myocardial or bone imaging, respectively. This distinction emphasizes the unique role of 99mTc sestamibi in hepatobiliary imaging compared to the others, which do not demonstrate similar levels of