This medicine uses a small amount of radiation to help doctors create images of your internal organs and diagnose problems.
The doctor will decide the exact amount. For adults, it's usually between 2 and 400 MBq. For children, the dose is based on body weight.
It is given as an injection into a vein in your arm or as eye drops.
This medicine is given as a single dose for the diagnostic test. An overdose is unlikely.