Which radiopharmaceutical is used for the evaluation of cardiac amyloidosis?

• A. Tc mertiatide (MAG-3)
• B. Tc mebrofenin
• C. Tc pyrophosphate (PYP)
• D. F-18 FDG

Answer: (C)

The use of technetium-99m pyrophosphate (PYP) is specifically relevant in the evaluation of cardiac amyloidosis due to its ability to bind to amyloid deposits in cardiac tissue. Cardiac amyloidosis is a condition characterized by the accumulation of amyloid fibrils in the heart, which can lead to significant cardiac dysfunction. When administered, PYP accumulates in areas where amyloid is present, allowing for imaging that can help in diagnosing the presence and extent of the disease.

This radiopharmaceutical is particularly effective because it leverages a mechanism of binding to the misfolded proteins that constitute the amyloid deposits, thus providing a visual representation of their distribution in the heart. This is crucial in differentiating cardiac amyloidosis from other forms of heart disease, thereby informing treatment decisions and patient management.

In contrast, other options like technetium mertiatide (MAG-3) and technetium mebrofenin are primarily used for renal imaging and liver function tests, respectively, and do not target amyloid deposits. F-18 FDG, although useful in metabolic imaging and assessing cardiac conditions, is not specific for amyloidosis and is typically used in the context of cancer or infection rather than for direct