11. Radioactive iodine (radio iodine) is given to patients with some forms of thyroid cancer in order to destroy the cancer cells. 13¹1 has a half-life of 8 days. Women who have been treated with 13¹1 are advised to not become pregnant for 180 days (approximately 6 months) to avoid the radioactive contamination of a developing fetus.

If a woman has been given a dose of 10 mCi (millicurie, a measurement of radiation), how much 13¹1 will still be in her system when she can safely become pregnant?