Test: Radionuclide Lung Scanning

Radionuclide lung scanning is used to diagnose pulmonary embolism. It involves two scans that are performed simultaneously: one to assess blood flow through the lungs and the other, which is called a ventilation scan, to assess airflow. A diagnosis can be made by comparing the ventilation scan and the blood flow scan because many lung disorders disrupt the flow of both blood and air in a specific area, whereas a pulmonary embolism disrupts only blood flow. The procedure usually takes about 20 minutes to perform.

During the procedure

A radioactive material is injected into a vein, and you inhale a radioactive gas. Scans may be taken from various angles using a gamma camera.

Comparison of air and blood flow

The ventilation scan here indicates normal airflow, but radioactivity is reduced in several areas on the blood flow scan. This result is characteristic of pulmonary embolism, in which only blood flow in a lung is affected.

From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.

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