Human skeleton. Coloured gamma scan (scintigram) of a healthy human skeleton. The skeleton is vital for bodily support, protection and movement. A gamma scan shows the concentration of an injected radioactive isotope (radionuclide) after it has accumulated in the body region to be observed. In this case Technetium-99m has been used to check the health of the bones. The isotope emits gamma rays which are detected as flashes of light by a gamma camera. The technique may be used to detect and assess the spread of cancer, as the isotope would concentrate in such a region, making the cancer appear as a hot spot"."