A gallium scan or gallium 67 scan is a nuclear medicine test that uses a radioactive tracer radiopharmaceutical to obtain images of a specific type of tissue, or disease state of tissue. Gallium salts like gallium citrate and gallium nitrate are used. The form of salt is not important, since it is the free dissolved gallium ion Ga⁺³ which is active. For these applications, the radioactive isotope ⁶⁷Ga is used. The body handles Ga⁺³ in many ways as though it were ferric (iron) ion, and thus it is bound (and concentrates) in areas of inflammation, such as infection, and also areas of rapid cell division. This allows such sites to be imaged by nuclear scan techniques.

The gallium scan was the standard for cancer diagnosis and staging until it was replaced by positron emission tomography or PET. It is still occasionally used to image inflammation and infection. After the tracer has been injected, images are taken 24, 48, and in some cases, 72, and 96 hours later. Each set of images takes between 30 and 60 minutes, depending on the size of the area being imaged. A gallium scan is often used in conjunction with a computer tomography scan to overlay "hot areas" with organ systems.

Terminology

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⁶⁷Ga citrate is a radionuclide tracer salt that is used during gallium scans.

"Hot areas" are areas that collect large amounts of tracer, because inflammation is present or rapid cell division is occurring.