Kaplan Nursing Entrance Practice Exam

What type of half-life is commonly expected for radioactive isotopes used in medicine?

1. Seconds long

2. Minutes long

3. Days long

4. Years long

The correct answer is: Days long

The commonly expected half-life for radioactive isotopes used in medicine is days long. This duration is ideal because it allows the radioactive material to decay to safer levels while still providing sufficient time for diagnostic or therapeutic purposes. In medical applications, such as imaging and treatment, isotopes need to be useful for enough time to allow for accurate diagnosis or effective treatment. If the half-life were too short (seconds or minutes), it may not be practical for medical procedures as the isotopes would decay too quickly, resulting in insufficient time to complete necessary imaging or therapeutic actions. On the other hand, if the half-life were too long (years), the isotopes could remain radioactive for extended periods, potentially posing health risks or complicating waste disposal processes. Thus, isotopes with a half-life measured in days strike a balance, allowing for effective medical use while minimizing risk and logistical challenges associated with longer-lived isotopes.