What is a gallium scan?

A gallium scan is a diagnostic test that looks for infection, inflammation, and tumors. The scan is generally performed in the nuclear medicine department of a hospital.

Gallium is a radioactive metal, which is mixed into a solution. It’s injected into your arm and moves through your blood, collecting in your organs and bones. After the injection, your body will be scanned to see where and how the gallium accumulated in your body.

Gallium is radioactive, but the risk of radiation exposure from this procedure is lower than from an X-ray or CT scan. Aside from the injection, the test is painless and requires very little preparation. However, the scan takes place several hours after the gallium injection, so the procedure needs to be scheduled accordingly.

Your doctor may order a gallium scan if you have unexplained pains or fever, or if there is a suspicion of cancer. Doctors also order the scan as a follow-up test for people who have been diagnosed or treated for cancer. The scan can also be used to inspect the lungs.

Purpose of a gallium scan of the lungs

In a gallium scan of the lungs, your lungs should look normal in size and texture, and should have collected very little gallium.

Abnormal results could indicate:

  • sarcoidosis, which occurs when chronic inflammatory cells form nodules on multiple organs
  • a respiratory infection
  • a tumor in the lung
  • scleroderma of the lung, which is an autoimmune disease that damages vital organs
  • a pulmonary embolus, which is an arterial blockage
  • primary pulmonary hypertension, which is high blood pressure in the arteries of your heart

This test isn’t foolproof. It’s important to note that not all cancers or small defects will show up in the gallium scan.

There’s no need to fast. And no medications are required for this test. In some cases, you may need to use a laxative or an enema to clear your bowels before the scan. This will prevent stool from interfering with the test results.

Notify your doctor if you’re pregnant, think you may be pregnant, or you’re nursing. Tests involving radiation are not recommended for women who are pregnant or nursing and should not be performed on very young children if possible.

This is an outpatient procedure, which means that you can go home on the day of the test.

When you arrive at the hospital, a technician will inject a gallium solution into a vein in your arm. You may feel a sharp prick and the injection site may be tender for a few minutes.

After the injection, you’ll be able to leave the hospital as the gallium begins moving through your bloodstream, collecting in your bones and organs. You’ll be asked to return to the hospital for the scan, usually between six and 48 hours after you receive the injection.

When you return, you’ll change into a hospital gown, remove all jewelry and other metal, and lie on your back on a firm table. A scanner will slowly move around your body while a special camera detects where the gallium has collected in your body. The camera’s images are viewed on a monitor.

The scanning process takes between 30 and 60 minutes. It’s important to remain completely still during the scan. The scanner doesn’t touch you, and the procedure is painless.

Some people find the hard table uncomfortable and have trouble remaining still. If you think you’ll have trouble lying still, tell your doctor before the test. Your doctor may give you a sedative or anti-anxiety medication to help.

Sometimes the scan may be repeated over several days. In this case, you won’t need additional gallium injections.

A radiologist will review your scans and send a report to your doctor. Normally, the gallium will collect in your:

  • bones
  • liver
  • breast tissue
  • spleen
  • large bowel

Cancer cells and other compromised tissues take up gallium easier than healthy tissues. Gallium that collects in other sites could be a sign of an infection, inflammation, or a tumor.

There’s a small risk of complications from radiation exposure, but it’s less than the risk involved with X-rays or CT scans. The risk of complications increases if you have many gallium scans over time.

A trace amount of gallium may remain in your tissues for a few weeks, but your body will eliminate the gallium naturally.