Isotope application help! please! (at least read my question)

1. why is nuclear notation useful if you are studying isotopes?
2. why would isotope notation be especially useful to a radiologic technician that supervises radiation therapy?

Just because it is an isotope doesn't mean it is the correct one to use. But even when it is, for proper documentation, you need to specify precisely what isotope was used. For instance, you would never want to see on a patient's record that they were prescribed penicillin, without specifying exactly which penicillin containing drug they were given, as there are a lot of penicillin drugs derivatives out there.

So in thyroid uses, it would be I-131 that would be prescribed.

But also, what does using iodine-131 also mean? A defined and well known half life.