A gallium 67 scan is a diagnostic procedure in nuclear medicine where gallium is used to detect tumors, inflammation and infection. Because gallium is chemically similar to iron, it binds to molecules in cells the same way iron does. Since iron also binds to tumors, inflammatory proteins and the cell walls of bacteria, the detection of the radioactive decay in a gamma ray camera will outline such structures in the body. Gallium scans have largely been replaced by PET scans for the detection of cancer, but is still one of the most effective ways of detecting chronic infection.