Human radioactivity

Medical imaging requires patients to be injected with or drink a radionuclide that can be “imaged” to show various organs and dysfunction. For the time that the radionuclide remains in your system (it is urinated out within a day or so), you are radioactive. According to the Health Physics Society, “our bodies are naturally radioactive, because we eat, drink, and breathe radioactive substances that are naturally present in the environment.”