Why is it best to use a radio active isotope that decays into a stable isotope?

Using a radioactive isotope that decays into a stable isotope is advantageous because it ensures that the radioactivity diminishes over time, reducing health risks associated with radiation exposure. Additionally, the stable end product poses no further environmental or biological hazards, making it safer for long-term use in applications like medical imaging or treatment. This approach also allows for precise tracking of the isotope's decay, facilitating accurate measurements and analyses.