A pulmonary ventilation/perfusion scan is a series of two scans
that measure how well air and blood are able to flow through
your lungs (ventilation scan), as well as the blood supply
through the lungs (perfusion scan). The scans are either
performed together or one after the other, but are often
discussed as one scan: the pulmonary ventilation/perfusion scan.
During a pulmonary ventilation/perfusion scan, a radioactive dye
is injected into your veins. This dye will show up on a special
type of scanner, and will give your doctor information about how
well your lungs are working. The dye will gather at areas of
abnormal blood flow, which may indicate a blockage in the lung
artery. This test may also be called a V/Q scan or a
radionuclide pulmonary scan. A pulmonary ventilation/perfusion
scan is used most frequently to screen for pulmonary embolus,
which is also known as a blood clot in the lungs. Symptoms of
pulmonary embolus include rapid heart rate, trouble breathing,
decreased oxygen saturation levels, and