A salivary gland scan uses a special camera and a tracer (radioactive chemical) to take pictures of the salivary glands. This can help your doctor find the cause of dry mouth (xerostomia) or swelling in the salivary glands.
During a salivary gland scan, the tracer liquid is put into a vein (IV) in your arm. The tracer moves through your blood and into the salivary glands. A special camera takes pictures to show how much tracer stays in the salivary glands.
Why It Is Done
A salivary gland scan is done to:
- Find the cause of swelling in the major salivary glands. Swelling may be caused by an infection (abscess), inflammation, or a pocket of fluid (cyst).
- See if a growth in the parotid gland is a benign tumour or may be cancer.
- Find the cause of dry mouth (xerostomia). Several problems can cause dry mouth, such as a blocked salivary duct, a growth in a salivary gland, or Sjögren's syndrome.
How To Prepare
Before the salivary gland scan, tell your doctor if you:
- Are or might be pregnant.
- Are breastfeeding. The radioactive tracer used in this test can get into your breast milk. Do not breastfeed your baby for 2 days after this test. During this time, you can give your baby breast milk you stored before the test, or you can give formula. Discard the breast milk you pump for 2 days after the test.
- Have had other nuclear scans recently. If so, the salivary gland scan may need to be delayed.
Talk to your doctor about any concerns you have regarding the need for the test, its risks, how it will be done, or what the results may mean. To help you understand the importance of this test, fill out the medical test information form .
How It Is Done
You will need to take off jewellery that may get in the way of the scan.
During a salivary gland scan, you will sit with the camera placed at your neck. A small amount of the tracer is put in your vein (IV).
The camera will scan for radiation released by the tracer. The pictures are taken every few minutes during the scan. You need to stay very still during the scan so the pictures are not blurry.
You may be asked to suck on a lemon after the first pictures are taken. This causes your salivary glands to release more saliva. Then more pictures are taken.
A salivary gland scan takes about 1 hour.
How It Feels
You will not feel pain during the test. You may feel a quick sting or pinch when the IV is put in your arm. The tracer may make you feel warm and flushed.
You may find it hard to lie still during the scan.
Allergic reactions to the tracer are very rare.
In some cases, soreness or swelling may develop at the IV site. Apply a moist, warm compress to your arm to relieve these symptoms.
Anytime you're exposed to radiation, there's a small chance of damage to cells or tissue. That's the case even with the low-level radioactive tracer used for this test. But the chance of damage is very low compared with the benefits of the test.
Most of the tracer will leave your body through your urine or stool within a day. So be sure to flush the toilet right after you use it, and wash your hands well with soap and water. The amount of radiation in the tracer is very small. This means it isn't a risk for people to be around you after the test.
The results of a salivary gland scan are usually available within 2 days.
The tracer moves evenly through the salivary glands and is released normally into the mouth.
The salivary ducts leading from the salivary glands are not blocked. Saliva is released in response to sucking on a lemon.
The tracer may not flow normally from the salivary glands into the mouth. This may be caused by a tumour pressing on the duct, a stone in the duct, or inflammation of the duct.
The flow of tracer through the salivary glands is decreased. This may point to a condition, such as Sjögren's syndrome.
The amount of tracer in the salivary glands in front of the ear is greatly increased. This may indicate inflammation or infection of the parotid glands (parotitis).
What Affects the Test
Reasons you may not be able to have the test or why the results may not be helpful include:
- Pregnancy. A salivary gland scan is not usually done during pregnancy, because the radiation could harm the developing baby (fetus).
- The inability to stay still during the test.
What To Think About
- In North America, a salivary gland scan is rarely done. Most often, a CT scan or magnetic resonance imaging (MRI) is done to look at the salivary glands. An ultrasound scan also may be done to look at the salivary glands. But a salivary scan is the only test that can see how well the salivary glands are working.
- Although a salivary gland scan may be done to evaluate dry mouth caused by Sjögren's syndrome, it usually is not used to diagnose this disease. But a salivary gland scan may be used to diagnose Sjögren's syndrome in a person who has rheumatoid arthritis.
Other Works Consulted
- Fischbach FT, Dunning MB III, eds. (2009). Manual of Laboratory and Diagnostic Tests, 8th ed. Philadelphia: Lippincott Williams and Wilkins.
Current as of: December 9, 2019
Author: Healthwise Staff
Medical Review: Adam Husney MD - Family Medicine
Brian D. O'Brien MD - Internal Medicine
Martin J. Gabica MD - Family Medicine
Howard Schaff MD - Diagnostic Radiology