Chapter 19, Problem 32A

Interpretation Introduction

Interpretation: The uses of radioisotopes in medical diagnosis or treatment of diseases needs to be explained.

Concept introduction: An isotope is an atom that has the different number of neutrons but same number of protons. Radioisotopes can be defined as an atom which have an unstable nucleus and readily undergoes radioactive decay.

Radioisotopes have wide application in medical diagnosis or treatment of diseases.

Answer to Problem 32A

The four radioisotopes are $I$ , $Tc$ , $Tl$ and $P$ .

Explanation of Solution

1. $I$ is used in diagnosis as well as treatment of thyroid cancer. The thyroid will absorb iodine to produce the iodine-containing thyroid hormones. A hyperactive thyroid gland will absorb the radioactive material which can then destroy excess thyroid tissue or any cancer of the thyroid.
2. $Tc$  isotope decays by emission of low intensity gamma ray which makes the radiation damage fairly negligible. It remains in the body for some time because its half-life is about six hours. $Tc$ is used to diagnose cardiac damage. $Tc$ flows in the blood stream; if there is less blood flow in the heart, then concentration of the isotope will be low in heart muscle.
3. $Tl$ can be used to assess cardiac damage and its working principle is similar to that of $Tc$ .
4. $P$ is a beta emitter with half life if 14.3 days and found good for skin diseases.

Conclusion

The four radioisotopes are $I$ , $Tc$ , $Tl$ and $P$ .