Will I be radioactive after radiation therapy?

It depends on the type of radiation therapy.

External beam radiation comes from a machine outside your body. It does not make you radioactive.

With systemic radiation therapy—a liquid radiation source you swallow or receive through an IV, such as radioactive iodine for some thyroid cancers—your body fluids, such as urine, sweat, and saliva, will give off radiation for a while.

If you receive a treatment that affects your body fluids, your care team will give you specific safety instructions to protect the people around you. They are the best source of guidance for your treatment.