Gamma rays are used in medical applications to treat cancer and to sterilize equipment. Gamma rays are also used as medical tracers to locate tumors.
Gamma rays are made of high-energy electromagnetic waves that pass through medical equipment easily. Gamma rays pass through a syringe's plastic packaging where they render viruses and bacteria inactive and sterilize the syringe. Syringes remain sterile as long as they remain inside the sealed plastic package.
Gamma emitters are used to create radioactive tracers, allowing doctors to investigate the body of a patient without the need to resort to surgery. This is possible because gamma rays pass through skin easily. A tracer is placed inside the body by injection or through ingestion. It is important that the radioactive tracer does not stay active inside the body too long because nuclear radiation can damage cells. After the tracer is given time to move through the body, a radiation detector is used to allow the doctor to see where the tracer has accumulated.
When gamma rays are used to treat cancer, the rays are focused on the tumor needing to be eradicated, as gamma rays can damage normal cells as well. Doctors rotate a wide beam of gamma rays around the patient's body while keeping the tumor at the center of the beam.