Lung gallium scan is a type of nuclear scan involving radioactive gallium (Ga.). The test helps determine whether a patient has inflammation in the lungs.

Gallium is injected into a vein. The scan will be taken 6 to 24 hours after the gallium is injected. (Test time depends on whether your condition is acute or chronic ).

During the test, you lie on a table that moves underneath a scanner called a gamma camera. The camera detects the rays emitted by the gallium. Images display on a computer screen.

During the scan, it is important that you remain still to get a clear image. The technologist can help make you comfortable before the scan begins. The test will take about 30 - 60 minutes.

You must sign an informed consent form. Several hours to 1 day before the scan, the injection of gallium will be administered to you at the hospital or doctor's office.

Just before the scan, remove jewelry, dentures, or other metal objects that can affect the scan. Replace the clothing on the upper half of your body with a hospital gown.

The injection of gallium will sting, and the puncture site may hurt when touched for several hours or days. The scan is painless. However, you must remain still. This may cause discomfort for some patients. The wait between the injection and scan can cause some patients to become agitated.

This test is most often performed when there is evidence of inflammation in the lungs (sarcoidosis).

The lungs should appear of normal size and texture with little uptake of gallium.

• Sarcoidosis
• Other respiratory infections

Additional conditions under which the test may be performed:

• Primary pulmonary hypertension
• Pulmonary embolus

There is some risk to children or fetuses. Because a pregnant or nursing woman may pass on radiation, special precautions will be made for these women.

For women who are not pregnant or nursing, and for men, there is very little risk from the radiation in gallium, because the amount is very small. There are increased risks with numerous exposures to radiation (such as x-rays, and scans), which you should discuss with the health care provider who recommends the test.

Usually a chest x-ray will indicate the need for this scan. Small defects may not be visible.