Final answer:
A desired characteristic of a diagnostic tracer is a short half-life, which limits the radiation dose to the patient. For example, Tc-99m, a commonly used diagnostic tracer, has a half-life of 6.01 hours.
Step-by-step explanation:
A desired characteristic of a diagnostic tracer is a short half-life.
Radioisotopes used in medicine typically have short half-lives, which make them suitable for medical applications. One reason for this is that short half-lives limit the radiation dose to the patient. Isotopes with short half-lives decay more quickly and therefore emit radiation for a shorter period of time, reducing the exposure to the patient.
For example, Tc-99m, a commonly used diagnostic tracer, has a half-life of 6.01 hours. This short half-life allows for efficient imaging while minimizing the patient's radiation exposure.