Final answer:
Medical isotopes like Tc-99m have short half-lives, typically a few hours to a few days, ensuring quick decay and minimizing radiation exposure.
Step-by-step explanation:
Medical isotopes tend to have short half-lives to minimize radioactive exposure and ensure they decay quickly once their diagnostic or therapeutic function is completed.
For instance, the widely used isotope Technetium-99m (Tc-99m) has a short half-life of 6.01 hours, making it ideal for medical applications but also impractical for long-term storage or transport. It's often generated on-site using Molybdenum-99 (Mo-99), which has a half-life of 66 hours and undergoes a process to produce Tc-99 for medical tests. The short half-life allows the isotopes to decay rapidly, reducing the risk of prolonged radiation exposure for patients.