Which radiopharmaceutical is commonly used in the assessment of lung perfusion scans?

The correct choice for assessing lung perfusion scans is 99mTc-MAA (macroaggregated albumin). This radiopharmaceutical is specifically designed for evaluating pulmonary blood flow. In a lung perfusion scan, 99mTc-MAA is injected into the bloodstream and distributes to the pulmonary capillaries, where it becomes trapped. The distribution of the macroaggregated particles allows for imaging of lung perfusion, identifying areas of normal and abnormal blood flow.

The choice of 99mTc-MAA for this application is primarily due to its size and properties, which ensure that the particles are effectively retained in the pulmonary vasculature, enabling accurate visualization of perfusion patterns. This information is crucial for diagnosing conditions such as pulmonary embolism or other vascular abnormalities in the lungs.

Other radiopharmaceuticals listed serve different purposes. For instance, 99mTc-pertechnetate is primarily used in thyroid imaging and gastrointestinal studies. 99mTc-bicisate is utilized in brain perfusion imaging and cerebral blood flow studies. 201-Tl Thallous Chloride is often employed in cardiac imaging, particularly in myocardial perfusion studies. Thus, 99mTc-MAA stands out as the most appropriate choice for lung perfusion