The gamma camera detects the energy from the radiotracer in your body and converts it into an image. The gamma camera itself does not emit any radiation. It has radiation detectors called gamma camera heads. Gamma cameras are based on the detection of gamma rays emitted from radionuclides. Radionuclides can be ingested or injected into the body. The camera accumulates counts of gamma photons, which are detected by crystals in the camera.