Final answer:
Radioactive Iodine (RAI; Sodium iodide 131) is generally not used in pregnant or breast-feeding patients due to risks to the fetus or infant. RAI is absorbed by the thyroid, but in pregnant women, it can cross the placenta, and it can also be excreted in breast milk. Safety is critical, and alternative treatments should be considered for these patient groups.
Step-by-step explanation:
Administering Radioactive Iodine (RAI; Sodium iodide 131) to pregnant or breast-feeding patients is generally contraindicated. Radioactive iodine is absorbed by thyroid cells, where it delivers localized radiation. This can be helpful in treating thyroid-related issues such as hyperthyroidism or thyroid cancer, as the thyroid gland is typically the only area of the body that absorbs significant amounts of iodine. However, in pregnant women, RAI can cross the placenta and affect the fetal thyroid gland, which begins to function at about 10 weeks of gestation and can lead to fetal hypothyroidism or damage to the developing thyroid gland. Similarly, RAI can also be excreted in breast milk and have effects on a breastfeeding infant's thyroid gland. Therefore, the use of RAI in these populations must be approached with caution and is usually avoided to prevent harm to the fetus or infant. When considering treatment with RAI, alternative diagnostic tools and treatment options should be explored for pregnant or breast-feeding patients.
The medical applications of radioactive isotopes like iodine-131 are extensive, including diagnosis and treatment of thyroid disorders, but safety is paramount, particularly when dealing with vulnerable populations such as pregnant or breast-feeding individuals. The half-life of iodine-131 is approximately 8 days, meaning precautions need to be taken during this period to minimize radiation exposure to others, including the avoidance of certain activities, like commercial flights, where radiation could trigger detectors.