Radioactivity in Nuclear Research
However, it is also possible to receive radioactivity due to a medical examination such as a nuclear scan. Nuclear tests usually involve very small amounts of a radioactive substances introduced to the body through the blood vessels. The injected substance settles, among other places, in locals where there is disease after which the majority is excreted, usually via the urine. The radioactive substance usually disappears from the body after a day. As a result, the radiation dose from such a treatment is very small.
A nuclear medicine doctor injects a radiopharmaceutical for a PET scan.