In which setting is MAA particles typically used?

MAA (macroaggregated albumin) particles are primarily used in the assessment of pulmonary embolism (PE). When performing a pulmonary perfusion scan, MAA particles are injected into the bloodstream and travel to the lungs. Since they aggregate in the pulmonary capillaries, their distribution can illustrate areas of the lung that may not be receiving adequate blood flow due to blockage from an embolism. This makes MAA highly valuable for diagnosing PE, as it allows for visualization of perfusion defects that are indicative of such blockages.

In contrast, the other options listed are associated with different diagnostic or therapeutic approaches. Radioiodine therapy is focused on treating conditions like hyperthyroidism or thyroid cancer, and does not utilize MAA. Bone scans primarily involve the use of radiotracers that highlight metabolic activity in bones rather than the macroaggregated albumin particles. Thyroid scans utilize radioiodine or technetium-based agents instead for assessing thyroid function or detecting nodules or tumors.

Understanding the specificity of MAA particles for pulmonary assessments emphasizes their unique role in nuclear medicine, particularly in identifying and characterizing pulmonary embolisms.