A gallium scan is a type of nuclear medicine diagnostic investigation that uses either a gallium-67 (67Ga) or gallium-68 (68Ga) radiopharmaceutical to obtain images of a specific type of tissue, or disease state of tissue. The gamma emission of gallium-67 is imaged by a gamma camera, while the positron emission of gallium-68 is imaged by positron emission tomography (PET). Gallium salts like gallium citrate and gallium nitrate may be used. The form of salt is not important, since it is the freely dissolved gallium ion Ga3+ which is active. As they are isotopic, Both 67Ga and 68Ga salts have the same uptake mechanisms. The gallium(III) is rapidly bound by transferrin, which then preferentially accumulates in tumors, inflammation, and both acute and chronic infection, allowing these pathological processes to be imaged. Gallium is particularly useful in imaging osteomyelitis that involves the spine, and in imaging older and chronic infections that may be the cause of a fever of unknown origin. Due to lack of disease specificity, imaging with radioactive gallium(III) salts or complexes, such as 67Ga citrate, has gradually become less important over time and is rarely used these days.