Nuclear Medicine! A patient sits with a syringe filled with sodium chloride, the chemical name for salt. Sodium is an electrolyte that regulates the amount of water in your body. Sodium chloride is used to prevent sodium loss during a nuclear medicine radiology test. The Radiologist next injects a syringe of radioactive glucose (simple sugar water) that will give off gamma rays to be filled during a PET scan (positron emission tomography). Healthcare and Medicine.