Look up "Gallium Scan". It is typically used to help determine if a cancer has metastasized.
You get injected with a gallium solution, and then wait two days while the radioactive ions collect in bones and tissues. When it's time for the scan, you lay on a table that effectively holds a body-sized film. The "scan" involves you laying still for 30 minutes while the film is exposed to your body.
Each time I had this done, I was told to stay away from small children for a week after the procedure.