Gallium Scan of the Body Health Article

Definition

A gallium scan of the body is a diagnostic imaging test that utilizes a radionuclide, Ga67, to detect areas of infection and inflammation, or to detect certain types of tumors.

Purpose

In cases where patients have a suspected infection or inflammation, a gallium scan is useful to establish the site of origin, particularly with bone or orthopedic infections, and with such diseases as sarcoidosis. Patients with a chronic infection accompanied with a fever of unknown origin are also candidates for a gallium scan. Gallium is also used to localize primary tumors and locate metastases; to diagnose Hodgkin's and other lymphomas; and to determine the stage of a lymphoma. Gallium scans are also performed to follow up patients who have received therapeutic treatment, to demonstrate the regression, progression, or recurrence of disease.

Precautions

Ga67 is radioactive; therefore, patients who are pregnant are cautioned against having this test unless the benefits outweigh the risks. Women who are breastfeeding will need to stop breastfeeding for a specified period of time, usually for several weeks, depending on the dose.

Description

The patient is required to come to the testing facility, usually a hospital nuclear medicine department or out-patient radiology facility, to receive an intravenous injection of the Ga67. After the injection, the patient must return anywhere from six hours to ten days later for the images, depending on the disease or condition being evaluated. The study itself takes approximately one hour, unless a more detailed SPECT (single photon emission computed tomography) is performed, which requires more time. The patient lies on an imaging table while a gamma camera obtains the necessary data to produce an image. In most cases, the camera is moved across the patient's body, or, in the case of a SPECT study, the camera will circle around the body. The camera does not give off radiation, but instead detects the radiation from any areas where the gallium has accumulated. Images are obtained, posteriorly, anteriorly, and sometimes laterally. The camera may occasionally touch the patient but will not cause any discomfort.

KEY TERMS

Gallium—An element whose radioactive form, Ga 67, is used for gallium scans.

Sarcoidosis—A chronic, progressive disease of unknown etiology that can affect almost any organ or tissue.

Preparation

No special preparation is necessary, although some patients may be required to have light or clear meals within a day or less of the procedure. Some patients may need to take laxatives or an enema prior to the scan, to eliminate any residual gallium from the bowel.

Aftercare

There is no particular aftercare required.

Complications

There are no complications. There is a minimal risk of exposure to radiation from the Ga67, but the exposure from one gallium scan is generally less than exposure from many common x-ray procedures.

Results

It is normal for the gallium to accumulate in the liver, spleen, bones, and large bowel. An abnormal concentration of gallium in areas other than those where it normally concentrates may indicate the presence of disease. Abnormal concentrations may be due to inflammation, infection, or presence of a tumor. Further investigation with ultrasound or CT is usually necessary to confirm the suspicions of abnormal findings, or to distinguish between a malignant and a benign tumor.

Health care team roles

The injection and scan are performed by a nuclear medicine technologist, who is specially trained to handle radioactive materials and to operate the equipment used for this study. The technologist will obtain any pertinent medical history and explain the test to the patient. The technologist processes the data obtained during the scan. A doctor who is a radiologist or nuclear medicine specialist interprets the images and may make recommendations for follow-up tests or for further diagnostic procedures. If the patient is hospitalized during the time in which the gallium scan is performed, the nursing staff may be needed to administer the enema and, if indicated, to oversee that the patient received a specified diet. The patient receives the results of this test from their personal physician or the doctor who ordered the test.

BOOKS

Illustrated Guide to Diagnostic Tests. Springhouse, PA: Springhouse Corporation, 1998.

Klingensmith, William C., III, M.D., Dennis Eshima, Ph.D., John Goddard, Ph.D. Nuclear Medicine Procedure Manual 2000-2001.

OTHER

"Gallium Scan." <http://www.healthanswers.com/library.MedEnc/enc/1264.asp>.

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