False colour bone scintigram of the spine and ribs of a person suffering from a secondary (metastatic) bone cancer affecting the dorsal spine. The tumour appears as the white area towards bottom of image. Bone scans record the distribution & intensity of gamma radiation emitted from a radionuclide that is injected into the body prior to taking the scan and which concentrates in bone. A crystal scintillator resolves emitted radiations as flashes of light, which are processed by a series of photomultiplier tubes. Cancerous bone concentrates the radionuclide more strongly than normal bone, and appears as brighter, inshot spotsins on the image.