Which pair of radiopharmaceuticals is commonly used for lung perfusion and ventilation imaging?

The use of 99mTc macroaggregated albumin (MAA) and 133Xe gas for lung perfusion and ventilation imaging is well-established. 99mTc MAA is injected into the bloodstream and collects in the lungs based on perfusion, providing essential information about blood flow within the pulmonary circulation. This allows for the assessment of conditions such as pulmonary embolism or other abnormalities affecting blood flow.

On the other hand, 133Xe gas is inhaled by the patient, allowing it to fill the alveoli in the lungs to assess ventilation. By coupling the data from perfusion imaging with MAA and ventilation imaging with 133Xe, it becomes possible to visualize and analyze the dual aspects of lung function.

This combination is effective because it gives a holistic view of lung health, distinguishing between areas with good perfusion but poor ventilation and vice versa, which can be crucial in diagnosing various pulmonary conditions. The synergistic use of these two agents enhances diagnostic accuracy.

In contrast, other combinations mentioned do not provide the same level of specificity for both perfusion and ventilation imaging in the lungs, making this pair the preferred choice in clinical practice.