Images of the lungs are taken through a lung scan, which is a specialized medical procedure that uses a radioactive substance called a radionuclide, as stated by Johns Hopkins Medicine. Another non-invasive technique that produces images of the lungs is known as chest radiography, which uses high-energy electromagnetic radiation in the form of X-rays.
The primary function of the lungs in the respiratory system is to facilitate the exchange of oxygen and carbon dioxide in the body. The manifestation of certain symptoms, including increased heart rates, difficulty in breathing, reduced oxygen supply and upper body discomfort, is typically associated with masses of clotted blood, air spaces or fatty deposits within the pulmonary blood vessels. A lung scan is normally recommended to pinpoint the exact location of the embolus.
Lung scans are generally classified into two types: ventilation and perfusion. A ventilation scan involves inhalation of the gaseous radionuclide, while a perfusion scan involves injection of the radioactive material. In a ventilation scan, a machine takes images of the lungs while the breath is held. The radionuclide should not be swallowed to prevent the digital images from being damaged. In a perfusion scan, an IV line is used to inject the radionuclide. Once the chemical has accumulated within the pulmonary vessels, a scanner snaps images of the lungs from various angles. A radiologist then interprets the images taken by the scanner to diagnose, treat or monitor a patient's conditions.