Which of the following statements is true for radioactive isotopes

Which of the following statements is true for radioactive isotopes?

a.They are frequently added to foods as nutritional supplements.

b.They do not affect living tissue.

c.They are never incorporated into organic compounds.

d.They can be used in conjunction with PET scans to diagnose a patient.

e.They do not occur naturally.

The correct answer and explanation is:

The correct answer is d. They can be used in conjunction with PET scans to diagnose a patient.

Explanation:

Radioactive isotopes are unstable forms of elements that decay over time, releasing radiation in the process. This radiation can be detected and used in various medical applications, including diagnostic imaging and treatment.

1. They are frequently added to foods as nutritional supplements (a): This statement is false. While radioactive isotopes have applications in medicine, they are not typically added to foods as nutritional supplements. In fact, they can be harmful if not properly controlled.
2. They do not affect living tissue (b): This is incorrect. The radiation emitted by radioactive isotopes can interact with living tissue and potentially cause damage. This is why radiation is both a useful tool in medical imaging (where the benefits outweigh the risks) and a concern when it comes to exposure.
3. They are never incorporated into organic compounds (c): This is also false. Radioactive isotopes can be incorporated into organic compounds, such as when radioactive carbon (carbon-14) is used to trace metabolic pathways or study biochemical processes. In fact, some medical imaging techniques, like Positron Emission Tomography (PET), often involve radioactive tracers that are organic molecules labeled with isotopes.
4. They can be used in conjunction with PET scans to diagnose a patient (d): This is the correct statement. Radioactive isotopes, such as fluorine-18, are used in PET scans. These isotopes emit positrons, which interact with electrons in the body, releasing gamma rays. These gamma rays are detected to produce detailed images of the body’s internal structures and identify issues like tumors or areas of abnormal activity.
5. They do not occur naturally (e): This is incorrect. Many radioactive isotopes do occur naturally. For example, uranium-238 and carbon-14 are naturally occurring isotopes found in the environment.

In summary, radioactive isotopes are crucial in medical diagnostics, particularly in imaging techniques like PET scans, which help detect diseases such as cancer.