Iodine 123 has a half life of?
**Core Concept**
Iodine-123 is a radioactive isotope of iodine used in nuclear medicine for diagnostic imaging, particularly in thyroid function tests and cardiac stress tests. Its half-life is a critical parameter in determining the optimal dosage and timing of its administration.
**Why the Correct Answer is Right**
Iodine-123 has a half-life of approximately 13.22 hours. This relatively short half-life allows for a rapid accumulation of the isotope in the target organ, followed by a quick clearance from the body, minimizing radiation exposure and reducing the risk of radiation-induced damage. The short half-life also enables the use of I-123 for dynamic imaging studies, where the isotope's distribution and clearance can be visualized over a short period.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect as the half-life of I-123 is not close to 1 hour.
* **Option B:** This option is incorrect as the half-life of I-123 is not close to 24 hours.
* **Option C:** This option is incorrect as the half-life of I-123 is not close to 40 hours.
**Clinical Pearl / High-Yield Fact**
When using I-123 for diagnostic imaging, it's essential to consider the isotope's short half-life and adjust the timing of the study accordingly to ensure optimal image quality and minimize radiation exposure.
**Correct Answer:** C. 13.22 hours