Norm of Gallium Scan of Brain
Normal pattern of brain-tissue gallium uptake as interpreted by a nuclear medicine physician.
Usage of Gallium Scan of Brain
Screening and localizing intracranial neoplasms, identification of cerebrovascular accident or tumor recurrence after surgical excision, and differentiation of localized inflammations of central nervous system (abscesses).
Description of Gallium Scan of Brain
A nuclear medicine scan in which radiopharmaceutical gallium-67 or gallium-68 is injected intravenously and a scintillation camera is used to obtain photographs of the meninges and brain soft tissue 24–48 hours later. The gallium is transported to the brain tissue via cerebrospinal fluid and plasma, where it binds to the transferrin receptor sites of soft-tissue cells of neutrophilic lactoferrin. Tumors and inflammatory lesions frequently contain large concentrations of these two proteins. A positive scan will have distinct patterns of gallium uptake that differ from normal tissue uptake. For example, neoplasms will appear as dense areas with increased gallium uptake, whereas inflammatory lesions (most frequently abscesses) appear on the scan as well-localized areas of increased gallium uptake that are encapsulated. Finally, cerebral hemorrhages will differ from normal gallium uptake, appearing as irregular, diffuse areas of uptake. This is attributable to the vascular occlusion and tissue damage associated with cerebrovascular accidents.
Professional Considerations of Gallium Scan of Brain
Consent form IS required.
Allergic reaction to the radiopharmaceutical (itching, hives, rash, tight feeling in the throat, shortness of breath, bronchospasm, anaphylaxis, death), infection.
Previous allergic reaction to the same radiopharmaceutical. This procedure is usually contraindicated during pregnancy and breast-feeding.
- The client is injected intravenously with radiopharmaceutical gallium-67 or gallium-68 from 6 to 48 hours before the scan.
- See Client and Family Teaching.
- Just before beginning the procedure, take a “time out” to verify the correct client, procedure, and site.
- The client is positioned under the scintillation camera, and serial images are obtained from anterior, posterior, lateral, and, occasionally, vertex views.
- The client must lie motionless throughout the scan.
- See Client and Family Teaching.
Client and Family Teaching
- Increase oral intake of fluids, where not contraindicated, beginning 24 hours before the scan.
- The scan takes 30–60 minutes and is painless.
- The camera may touch the body and will make a clicking noise during the scan.
- It is important to lie motionless during the scan.
- Drink 6–8 glasses of water and other fluids each day for 2 days after the test (unless contraindicated).
- Results are normally available 24 hours after the completion of the scan.
Factors That Affect Results
- Lesions <1–2 cm in size may not be detectable with a gallium scan.
- Lesions located at the base of the brain, such as pituitary adenomas, may be difficult to detect because of the increased vascularity of the area and the difficulty in positioning the camera for clear images.
- False-positive results may be obtained in the presence of leukopenia.
- Pediatric neoplasms will most frequently appear intrafrontally, whereas adult neoplasms will most often be located supratentorially.
- Gallium is excreted by the kidney and colon in 24–48 hours.
- Gallium scanning does not differentiate malignant from benign tumors.
- Health care professionals working in a nuclear medicine area must follow federal standards set by the Nuclear Regulatory Commission. These standards include precautions for handling the radioactive material and monitoring of potential radiation exposure.