Respuesta :

by injecting a radioactive isotope that travels to the target tissue and measures the amount of radioactive decay.

Hope this helps!

Answer:

Running tests.

Explanation:

Doctors usually run different type of tests, depending on the specific case. In medicine, they have like standard values for a health system, organ, person, or whatever they are seeing, if the patient is outside this normal values, it's because there's a medical problem.