The Contribution of Nuclear Medicine to Pulmonary Imaging

A variety of nuclear medicine imaging techniques have been applied to imaging of the chest. Several radiopharmaceuticals were designed specifically to diagnose changes in pulmonary physiology caused by pathologic processes. Intravenous injection of 99mTc macroaggregated albumin (MAA) permits identification of local and regional changes in pulmonary arterial perfusion, initially used to identify changes related to pulmonary embolism and later applied to evaluation of pulmonary arterial flow distribution in patients with congenital heart disease. Ventilation studies with noble gases such as 133Xe and 81mkrypton allow recognition of local and regional changes in ventilation and are used with 99mTc MAA perfusion imaging for the identification of pulmonary emboli. Radioaerosols, particularly 99mTc DTPA, can also demonstrate local and regional ventilation abnormalities. Aspiration of saliva can be detected by the radionuclide salivagram. Positron emission tomography (PET) after intravenous injection of [18F]fluoro-2-deoxyglucose (FDG) can be used to localize and follow neoplastic and inflammatory processes in the chest.