Salivary Gland Scan Health Article

Definition

A salivary gland scan is a nuclear medicine test that establishes the function of the salivary glands. The salivary glands include the parotid glands and submandibular glands, which are located on both sides of the neck below the ears and jaw. Salivary gland function is determined by the pattern of uptake and secretion of a radioactive tracer, usually Tc99m (Technium 99). The scan also demonstrates the relative size and shape of the salivary glands.

Purpose

A salivary gland scan is indicated when a patient has recurring salivary gland swelling due to either infection, inflammation, or obstruction. Salivary gland scans can detect salivary gland tumors, and can help evaluate the glands of patients with persistent dry mouth.

Precautions

Salivary gland scans are a safe, effective way to diagnose salivary gland pathology. The level of radioactivity used to obtain the images is low, however, pregnant patients are cautioned not to have this test unless necessary. Women who are breastfeeding are advised to stop breastfeeding for a specific period of time, depending on the dose administered. Other recent nuclear medicine tests may affect the results of this scan, and it may be necessary to wait until previously administered radio-pharmaceuticals have been cleared from the body before undergoing this test.

Description

A salivary gland scan, also called a parotid gland scan, is a non-invasive test. It is typically performed in a hospital radiology or nuclear medicine department or out-patient radiology facility. The patient is injected with a low-level radioactive marker and is positioned in front of or under a gamma scintillation camera, which detects the radiation and produces an image. In some facilities, imaging begins immediately after the injection to observe the progressive accumulation of the radioactive tracer in the glands. If indicated, an additional procedure can be done after the initial images are obtained. The patient is given a sour substance, known as a sialogogue, such as a lemon drop or some lemon juice, to stimulate the emptying of the salivary glands. Another set of images is then made for comparison purposes. The entire process takes about 30 to 45 minutes.

Preparation

No special preparations are needed for this test. It is not necessary to fast or to restrict medications before testing. Any blood to be drawn for other tests may need to be taken before the radiopharmaceutical is injected. Patients must remove any metal objects from the face and neck and may be asked to remove dentures.

Images of the thyroid gland is typically included when imaging the salivary glands. Therefore, it should be noted if the patient is taking any medication that inhibits the uptake of the radiopharmaceutical in the thyroid gland.

Aftercare

Patients can return to normal activities immediately.

Complications

A salivary gland scan is a safe test, and there are generally no complications associated with it.

Results

A normal study reflects a normal position, size, and shape of the salivary glands, and will also demonstrate proper emptying of the glands after the oral administration

of the sialogogue. Abnormally functioning salivary glands, due to conditions such as Sjögren's syndrome, fail to exhibit a normal uptake and secretion pattern. Some tumors, such as a Warthin's tumor, prevent the emptying of the salivary gland and are seen as areas of increased concentration of radionuclide. Metastatic lesions, cysts, and abscesses are seen as areas of decreased concentration of radionuclide. This test does not differentiate between benign and malignant lesions. This requires other diagnostic imaging tests such as CT, MRI, or ultrasound.

Health care team roles

The radionuclide is administered by a nuclear medicine technologist, who is specially trained to handle radioactive materials and operate the equipment in a nuclear medicine department. The technologist may obtain pertinent patient medical history and describe the testing procedure to the patient. All data collected is interpreted by a radiologist or nuclear medicine specialist. Results of the test are sent to the referring physician.

KEY TERMS

Radiopharmaceutical—A radioactive chemical used for diagnostic or therapeutic purposes.

Sjogren's syndrome—A disease, often associated with rheumatoid arthritis or lupus, that causes dry mouth, dry eyes, and swollen salivary glands.

Warthin's tumor—A benign tumor of the parotid gland.

BOOKS

Klingensmith III, M.D., Wm. C., Dennis Eshima, Ph.D., John Goddard, Ph.D. Nuclear Medicine Procedure Manual. 2000.

OTHER

Harrison's Online "Salivary Gland Scan." <http://www.healthgate.com/HealthGate/free/dph/static/dph.0210.html>

Christine Miner Minderovic, B.S., R.T., R.D.M.S.