If you or someone you love is having a lobectomy, a pneumonectomy, or another surgery for lung cancer, the surgeon may require a ventilation/perfusion scan — also called a V/Q scan — before the procedure. Unless you’ve had one before, this scan may sound intimidating or nerve-wracking.

Getting a V/Q scan before surgery can give doctors valuable information about how your lungs are functioning. Here’s what you need to know to understand V/Q scans and why your doctor might request one.

What Is a V/Q Scan?

A V/Q scan includes two scans that are usually done together — a ventilation (V) scan and a perfusion (Q) scan. The ventilation part of the scan measures how well the air you breathe in is flowing through your lungs. The perfusion part of the scan measures where blood flows when it goes through the blood vessels inside your lungs.

Your doctors will look for certain patterns when it comes to where the air is flowing and where the blood is going. Notable differences to a normal pattern can indicate some sort of blockage in your lungs.

Both parts of the scan involve using a small amount of radioactive substances to help your doctor visualize how air and blood flow through your lungs. For the ventilation scan, you’ll inhale a radioactive tracer. For the perfusion scan, a health care provider will inject the tracer into your bloodstream through an intravenous line in your arm.

When Is a V/Q Scan Used?

V/Q scans are used to determine whether there is a blockage in your lungs. Most of the time, doctors are looking for pulmonary embolisms — generally blood clots — that can prevent your lungs from working properly.

You may be at a higher risk of blood clots in your airway if you’ve been diagnosed with cancer or another lung issue. If you have lung cancer, your surgeon will have you get a V/Q scan to check for blood clots before they perform surgery.

Surgeons also use V/Q lung scans to see how well your lungs are functioning with lung cancer. They need to ensure you have the lung function to get the oxygen you need during and after surgery. V/Q scans are even more useful and necessary if you have a history of smoking or have been diagnosed with another type of lung disease.

What To Expect Before, During, and After a V/Q Scan

If you’re nervous about a V/Q scan, it can help to understand what to expect and what you’ll need to do to prepare for the scan. Here’s the process of getting a V/Q scan.

Before the Scan

There’s not a lot that you’ll need to do before getting a lung V/Q scan. Doctors will want you to have a chest X-ray within 24 hours before the scan. You may be able to get an X-ray as part of the process and on the same day as your V/Q test. If not, you’ll need to schedule the chest X-ray separately. The chest X-ray helps your doctors interpret the results of the V/Q scan.

You should also make sure you understand the entire process before getting your scan and ask any questions you might have. That way, you’ll feel more confident going into the scan and you won’t have to worry as much.

During the Scan

Your scans will be performed one right after the other. The ventilation scan is usually done first.

For the ventilation scan, you can expect to:

• Lie down on a table. Get comfortable and prepare to stay still during the scan.
• Wear a mouthpiece or a mask that fits over your nose and your mouth.
• Inhale the radioactive substance. This usually takes about five minutes.
• Let the radiology staff position you so the camera can get the images it needs.
• Breathe steadily while the camera takes pictures of your lungs.
• Reposition as needed with a health care provider’s guidance to get the pictures your doctors need.
• Remove the mouthpiece or mask. Medical staff may continue to take more pictures.
• Only move when instructed to do so.

After the ventilation scan, health care providers will do the perfusion scan. For this scan, you can expect:

• A medical staff member will insert an IV line into a vein in your arm.
• They will administer a radioactive substance through the IV and wait to make sure the radioactive substance has traveled to your lungs.
• Medical staff will position your body to get the pictures they need.
• You will have to lie very still so the pictures are clear and not blurry.
• Medical staff may reposition you so they can get all of the different angles and images they need.
• A medical staff member will remove the IV after the test is complete.

The whole process usually takes between 45 and 60 minutes. Each scan is about 15 minutes, and transitions take up the rest of the time.

After the Scan

Recovering from a V/Q scan is much easier than recovering from other procedures related to lung cancer. After the scan, the radioactive substances will leave your body on their own. You’ll exhale the substance you had inhaled, and your body will filter out the other in your bloodstream. It can take a few hours or days for your body to get rid of these substances completely.

You should be able to return to your normal routine shortly after the scans. You can even drive yourself home from the tests. You can eat and drink normally and participate in your usual activities afterward.

If you’re breastfeeding or otherwise feeding a baby with milk from your body, get medical advice about how soon you can go back to doing so. Your doctor may want you to wait a day or two to make sure the radioactive materials have left your body and breast milk.

Your doctor will likely have your scan results within 24 hours. If they’re doing the scans before surgery, they may get them even faster. They will discuss and interpret the results with you.

Are There Risks Associated With a V/Q Scan?

There are only a few risks associated with having a V/Q scan.

First, you’ll be exposed to radiation. If you’re pregnant, there’s no way to protect a fetus from radiation exposure from the scan. Most oncology teams will request another kind of test if you’re pregnant. You’ll need to work with your oncology team to make sure they can get the information they need to treat your lung cancer effectively.

Secondly, some people have an allergic reaction to the radioactive material. These reactions are usually not a major problem, but they’re something to be aware of. If you’ve had allergic reactions to radioactive materials before, be sure to tell your doctor before getting a V/Q scan.

Finally, getting an IV line inserted may feel uncomfortable. The process usually only lasts a few seconds, but it can be difficult if you struggle with needles. You and your health care team can talk about what you might need to make this process easier. You may experience a minor bruise where the IV line was inserted, but it should fade over several days after the scan.

Talk With Others Who Understand

MyLungCancerTeam is the social network for people with lung cancer and their loved ones. On MyLungCancerTeam, more than 12,000 members come together to ask questions, give advice, and share their stories with others who understand life with lung cancer.

Are you preparing to get a V/Q scan or have you gotten one before lung cancer surgery? What was your experience like? Share your story in the comments below, or start a conversation by posting on your Activities page.