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What To Expect Before a Lung Ventilation/Perfusion Scan?

A lung ventilation/perfusion (VQ) scan may be done during an emergency to help diagnose or rule out a pulmonary embolism (PE). A PE is a sudden blockage in a lung artery. This serious condition can cause low blood oxygen levels, damage to the lungs, or even death.

If your VQ scan isn't done during an emergency, your doctor will tell you how to prepare for the test. Most people don't need to take any special steps to prepare for a VQ scan.

Your doctor may ask you to wear clothing that has no metal hooks or snaps. These materials can block the scanner's view. Or, you may be asked to wear a hospital gown for the test.

Tell your doctor whether you're pregnant or may be pregnant. If possible, you should avoid radiation exposure during pregnancy, as it may harm the fetus.

You and your doctor will decide whether the benefits of a VQ scan outweigh the small risk to the fetus, or whether another test might be better.

If you're breastfeeding, ask your doctor how long you should wait after the test before you breastfeed. The radioisotopes used for VQ scans can pass through your breast milk to your baby.

You may want to prepare for the scan by pumping and saving milk for 24 to 48 hours in advance. You can bottle-feed your baby in the hours after the VQ scan.

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Lung Ventilation/Perfusion Scan Clinical Trials

Clinical trials are research studies that explore whether a medical strategy, treatment, or device is safe and effective for humans. To find clinical trials that are currently underway for Lung Ventilation/Perfusion Scan, visit

July 25, 2014 Last Updated Icon

The NHLBI updates Health Topics articles on a biennial cycle based on a thorough review of research findings and new literature. The articles also are updated as needed if important new research is published. The date on each Health Topics article reflects when the content was originally posted or last revised.