Applications of Radioisotopes in Different Fields

Some radioisotopes exist naturally. For example 3H1, 17O8, 40K19. While other radioisotopes are produced artificially by transmutation in a nuclear reactor by this processes:

i. A stable nucleus is bombarded by high speed alpha particles, neutrons or protons to produce artificial radioisotopes.
ii. The bombarding particles are trapped in the nucleus creating a radioactive isotopes.

Among the properties of radioisotopes are:

i. Emits radioactive radiation.
ii. Radioactive radiations can kill cells.
iii. Radioactive radiations have different penetrating ability with materials of different thickness and densities.
iv. Radioactive radiations can cause cell mutation.
v. Radioactive radiations can ionise molecules.
vi. Its activity decreases with time.
vii. Radioisotopes have the same chemical properties as non-radioactive isotopes of the same element.

Applications of radioisotopes in Medicine

1. To diagnose of thyroid disease using iodine-123.
2. To treat an overactive thyroid gland and certain kinds of thyroid cancer by using sodium iodide labelled with radioactive iodine.
3. To detect position of blood clots or thrombosis using Sodium-24 injected in the bloodstream.
4. To detect and treat brain tumor using phosphorus-32
5. To study the circulation of iron in the blood using iron-59
6. To sterilise medical equipments and to destroy cancer cells in radiotherapy radioisotope cobalt-60 is used.

Applications of radioisotopes in Industries

1. The thickness of paper, plastics, clothes and metal sheets need to be standardised and this is done by placing a raioactive source at one side of the material and a detector on the other side.
2. For sheets of metal, gamma ray is used. For plastics, clothes and paper, beta particles are used.
3. The detector will register a higher count if the material is too thin and lower register if too thick. The computer will make adjustments according to the thickness of the material.
4. This mechanism is also used to ensure that containers such as cans and food packages are filled to the specified amount.
5. Radioisotope is added to engine oil so that its level of wear and tear can be determined.
6. In order to kill germs that cause food to spoil quickly, gamma rays are used.
7. If exposed to gamma ray, latex becomes harder without the need for adding sulphur.

Applications of radioisotopes in Agriculture

1. Pests can be killed using radioactive rays esp using gamma rays.
2. To stop pests from reproducing, induced mutation by using gamma rays can be employed. But this has the probability of producing GMO and resistant pests.
3. To be used as tracers in the effectiveness of fertilisers using nitrogen-15 and phosphorus -32.
4. To induce genetic mutation in a plant in order to produce a better strain which has higher resistance against pest and diseases.

Applications of radioisotopes in Archaeology

1. To determine the age of artifacts, the carbon dating method is used.

Consider this paragraph:

Cosmic radiations from outer space displaced neutrons from nuclei in the Earth's outer atmosphere. These neutrons then collide with nitrogen nuclei to produce carbon-14. Living organisms like plants and animals absorb and give out carbon-14 when they are alive. The half-life of carbon-14 is about 5730 years. So there is negligible disintegration over the lifetime of most organisms. However when they die, no  more absorption of carbon-14 occurs. The C-14 taken starts to decay into N-14 by beta emission. The percentage of carbon 14 in dead plant decreases as the carbon 14 disintegrates. After 5730 years, the percentage of carbon 14 falls to 50 percent of its initial value. The activity of atoms is proportional to the number of undecayed atoms. By comparing the activity of the dead sample of the same mass of the living sample, its age can be estimated.

2. To measure geological time.

During the formation of rocks, some radioisotopes such as uranium-238 are trapped. As the decay continues, the proportion of uranium-238 decreases slowly resulting in the equally slow growth of its product lead-206. An estimate of the age of the rock can be inferred from the relative proportions of lead and uranium in the rock.


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Jonathan Chan said...

Thx for the notes.

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