Positron emission tomography (PET) scans are common tools that many oncologists use to diagnose lung cancer, stage lung cancer, and more. If you have recently been diagnosed with lung cancer or your doctor wants to confirm a diagnosis, you may be asked to get one of these scans. You may also undergo PET scans during lung cancer treatment to monitor the disease’s progression and determine the effectiveness of your treatment.

Before you go in for your PET scan, it can help to understand everything you can about the procedure. That way, you’ll be prepared for what will happen, and you’ll know what types of results to expect.

What Is a PET Scan?

A PET scan produces 3D pictures of your whole body. PET scans are relatively noninvasive — they are performed using a slightly radioactive drug that is injected into your body. The drug (or radiotracer) shows doctors where the cells in your body show increased activity. These areas can indicate the presence of cancer and other health conditions.

A tracer is usually a radioactive form of sugar called fluorodeoxyglucose (FDG or FD glucose). Cancer cells usually grow quickly, and they need sugar to fuel this growth. Cancerous cells tend to absorb the radioactive sugar quickly, and this activity shows up as white or lighter spots on a PET scan. These scans are also called FDG-PET scans.

These imaging techniques are usually performed as outpatient procedures, though you will likely be in the nuclear medicine or radiology department for at least a couple of hours. Medical staff will inject the radioactive material, then wait approximately an hour for it to spread through your body. Then, a technician will put you in the scanning machine. The scan itself takes about an hour.

Your doctor may order a PET scan or a PET-CT scan. A PET-CT scan is the same as a PET scan, with the addition of another imaging test called a CT scan. The combination of these two scans gives doctors even more information to work with when diagnosing a condition like lung cancer.

Why Do Doctors Order Lung PET Scans?

Doctors use PET scans for several purposes.

Diagnosing Lung Cancer

The PET scan allows your doctors to see whether you have tumors growing on, in, or around your lungs. Scans can also show whether a particular lump or spot on your lungs may be malignant (cancerous). To diagnose lung cancer, PET scans are often used alongside chest X-rays, other X-rays, CT imaging, MRI imaging, and more.

Staging Lung Cancer

PET scans can show doctors how big tumors are, how many tumors there are, where exactly tumors are located, and whether your body shows signs of cancer activity beyond your lungs (such as metastasis, or spreading, into your lymph nodes). All of this information helps your doctors determine what stage of lung cancer you should be diagnosed with.

Determining a Lung Cancer Treatment Plan

PET images can show oncologists where they should take a biopsy to test for lung cancer. The images can also help doctors determine which treatment options would be best, based on factors like the specifics of a person’s tumor or tumors.

Evaluating Treatment Effectiveness

A PET scan can show doctors whether lung cancer is responding to current treatments. It can show tumors getting larger or smaller, spreading, or even disappearing. Using PET scans in this way is controversial, but many doctors believe these images, in addition to other tests, are helpful in evaluating whether a particular treatment is working.

Managing Ongoing Care

PET scans can be used to follow up and determine whether lung cancer has returned. This type of follow-up can help doctors catch returned cancer early so it can be treated effectively. This is a controversial use of PET scans, however, as some doctors believe that the scans are not worth their high cost and the exposure to radioactive tracers.

How To Prepare for a Lung PET Scan

Your health care provider should give you specifics for preparing for your PET scan. Make sure to inform your doctor if you:

• Have had serious allergic reactions in the past
• Have recently had an acute illness
• Have diabetes or other chronic medical conditions
• Have any reason to believe that you might be pregnant
• Have had claustrophobia before, particularly when getting a medical scan
• Have been on any medications, including over-the-counter medications, prescribed medications, or supplements
• Have been breastfeeding

You will likely need to refrain from eating for at least a few hours before the scan, though some scans require you not to eat for six hours. You may also be asked to avoid exercise for up to 24 hours before the scan.

What To Expect When Getting a Lung PET Scan

Make sure you arrive early so you can check in and fill out any necessary paperwork without feeling rushed. When you are taken back for the procedure, you will be given a chance to use the bathroom and be asked to put on a hospital gown.

Next, you will receive the radioactive tracer. Most of the time, the tracer is injected intravenously (with an IV). Your technician will give you specific instructions so you know what you need to do. Once you have received the tracer, you will be asked to wait for up to an hour while your body absorbs and distributes it.

When your body has had time to absorb the tracer, you will be taken to the scanning room. A PET scanner looks like a large, metal bagel. You will be asked to lie on a padded table that can slide in and out of the scanner. The radiologist will make you as comfortable as possible before the test begins.

The technician will leave the room during the scan, but they will be able to hear you and see you on closed-circuit television. During the scan, the table will slide into the hole in the middle of the machine. It will take pictures of your whole body. You will need to remain as still as possible so that these pictures are clear. Otherwise, you may have to stay in the machine longer or redo the scan at a later date.

If you feel anxious during the scan, you can let the technician know. If you know beforehand that you might feel anxious, you can ask for medication that will help you relax.

After your scan, you should be able to go on with your day. You should receive results from your PET imaging scan within a few days. This waiting period can be a time of heightened anxiety for many people. As one MyLungCancerTeam member recommended, “Try and stay busy. I get my PET scan results and my brain MRI results both on Friday. The waiting is hard.”

Remember that your doctor only wants the best for you, and that it is always better to have more information about your condition so you can make informed choices about treatment. Before long, you should know what your PET scan showed.

Get Support From Others Who Understand

If you or someone you love has been diagnosed with lung cancer, it’s likely you could use some support. At MyLungCancerTeam, the social network for people with lung cancer and their loved ones, thousands of members come together to ask questions, give advice, and share their experiences with others who understand life with lung cancer.

Have you had a lung PET scan? Share your experience or tips in the comments below or by posting on MyLungCancerTeam.