What To Expect During a Lung Ventilation/Perfusion Scan

A lung ventilation/perfusion (VQ) scan is done at a radiology clinic.

You will lie on a table for about 1 hour and have two types of scans: ventilation and perfusion. The ventilation scan shows where air flows in your lungs. The perfusion scan shows where blood flows in your lungs.

You must lie very still for the tests, or the pictures may blur. If you’re having trouble staying still, your doctor may give you medicine to help you relax.

Both scans use radioisotopes (a low-risk radioactive substance). This substance releases energy inside your body. Special scanners outside of your body use the energy to create images of air and blood flow to your lungs.

The radioisotopes used in VQ scans can cause an allergic reaction, including itching and hives. If this happens, your doctor will give you medicine to relieve the symptoms.

Ventilation

For this scan, you lie on an open table that moves under the arm of the scanner. You wear a breathing mask over your nose and mouth and inhale a small amount of radioisotope gas mixed with oxygen.

As you breathe, the scanner takes pictures that show air going into your lungs. You’ll need to hold your breath for a few seconds at the start of each picture.

The scan is painless, and each picture takes only a few minutes. However, wearing the mask can make some people feel anxious. If this happens, your doctor may give you medicine to help you relax.

Perfusion

For this scan, a member of the health care team will inject a small amount of radioisotope into a vein in your arm. The scanner then takes pictures of blood flow through your lungs.

The scan itself doesn’t hurt, but you may feel some discomfort when the radioisotopes are injected.