How long will you be radioactive after a nuclear medicine thyroid scan?

After receiving a standard dose of radioactive iodine-131 for thyroid scanning, the radioactivity in your body will gradually decrease over time. The half-life of iodine-131 is 8.02 days, which means that it takes about 8 days for half of the radioactivity to decay.

This means that after 8 days, your body will contain about half the amount of radioactivity it did immediately after the scan. After another 8 days, your body will contain about half of the remaining radioactivity, and so on.

It's important to note that even though the radioactivity in your body will decrease over time, it will never completely disappear. There will always be a small amount of radioactivity remaining in your body, but this amount will be so small that it will not pose any health risks.

The amount of time it takes for the radioactivity to become negligible will vary from person to person, but it is typically within a few weeks or months.