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July 1966

Lung Scanning: Its Use in Diagnosis of Disorders of the Pulmonary Circulation

Arch Intern Med. 1966;118(1):65-69. doi:10.1001/archinte.1966.00290130067012

LUNG scanning is the procedure which records in two dimensions the distribution of intravenously injected radionuclides trapped in the pulmonary circulation. The pulmonary circulation performs several functions.1 Primarily thought of as a means of gas exchange, it also serves as a blood reservoir for the left side of the heart, as a source of nourishment to the structures of the lung beyond the terminal bronchioles, as a means of removal of fluid from the alveoli, and as a filtration system which prevents particulate matter from entering the systemic circulation. This last function provides the basis for clinical lung scanning. The pulmonary vessels filter and trap particles larger than 10μ with an efficiency of 90%-95% in a single circulation. Intravenous injection of proper-sized particles labeled with an appropriate γemitting radionuclide results in their retention by the pulmonary arterioles. Scanning the area with a suitable detecting device which proportionately records the