The basis of pulmonary scintigraphy is the detection of gamma rays emitted from the lung after administration of a radioactive tracer.
See Lung Scintigraphy.

See also Aerosol Ventilation Scintigraphy, Gas Ventilation Scintigraphy, Pulmonary Perfusion Scintigraphy, Computed Tomography Pulmonary Angiography and Lung Imaging.

Inhalation scintigraphy is a type of lung imaging with radioactive aerosols. Inhalation scintigraphy can be accomplished with 99mTc-DTPA or other aerosols. The patient inhales the particles over a special system.

See also Pulmonary Scintigraphy, Aerosol Ventilation Scintigraphy and Gas Ventilation Scintigraphy.

Scintigraphic imaging of the lungs is a sensitive diagnostic imaging tool to detect certain kinds of pulmonary abnormalities in correlation with clinical data and chest radiographs. Pulmonary scintigraphy is particularly useful in diagnosing medical conditions such as pulmonary embolism, bronchial carcinoma and chronic obstructive pulmonary disease.
Lung scintigraphy can be performed with radioaerosols, gaseous radiopharmaceuticals and technetium-99m-labeled perfusion agents that are localized by temporary capillary blockade.

Different types of lung scintigraphy include:
The choice of the radioactive tracer varies and depends on the pulmonary function to be imaged. The radioactive tracer distribution within the lungs can be displayed on a computer screen via a gamma camera, a scanner or some other similarly suitable detector that records the radioactive disintegrations emitted by the patient. The images obtained present chromatic variations proportional to the regional radioactivity.

The pulmonary perfusion scintigraphy records the distribution of pulmonary arterial blood flow. The most common indication for lung scintigraphy is the detection of pulmonary embolism. The most widely used radiopharmaceuticals are technetium-99m MAA (macroaggregates of albumin) or 99mTc-HAM. Other radiopharmaceuticals include sulphur colloid macroaggregated albumin, radioactive albumin microspheres and albumin labeled with I-131, or I-113m.
Perfusion imaging of the bronchopulmonary system is based on the principle of capillary blockade. The perfusion study is accomplished by injecting 40 to 160 MBq (1-4 mCi) of the radiopharmaceutical and during repeated deep inhalation. The aggregates are extracted during their first pass through the lung, thus imaging can begin immediately. Pulmonary perfusion scintigraphy is particularly useful in combination with gas ventilation scintigraphy and aerosol ventilation scintigraphy.

See also Inhalation Scintigraphy.

(MAA) Macroaggregated albumin is used in pulmonary perfusion scintigraphy to record the pulmonary circulation. Macroaggregated albumin is usually prepared by heating human serum albumin. The produced particle sizes range from 10 to 100 µm in diameter. The albumin may be labeled with 131I, 99mTc, or 113mI.