Final answer:
The type of radiation emitted and the half-life of an isotope determine its application, such as cobalt-60 with a 5.27-year half-life used in cancer treatment. Radiation intensity is directly proportional to the decay rate, and isotopes with short half-lives are preferred in medical imaging to minimize patient radiation exposure.
Step-by-step explanation:
The type of radiation emitted and the half-life of an isotope are crucial in determining its suitability for various applications. For instance, cobalt-60, which emits gamma rays, is used in cancer treatment because of its ability to target diseased cells effectively. The half-life of an isotope like cobalt-60, which is 5.27 years, indicates how long the isotope will remain active and at what rate it will decay. Since the radiation intensity is directly proportional to the rate of decay and the amount of the substance, a cobalt-60 source must be replaced regularly to maintain its effectiveness in cancer therapy. Similarly, in medical imaging, isotopes with short half-lives are employed to minimize the radiation dose to the patient.