3.10 Radioactive Isotopes and Their Uses

• Radioactive Isotopes: These are isotopes whose nuclei spontaneously decay, emitting alpha (α), beta (β), and gamma (γ) rays. There are over 3000 known isotopes, some natural and some synthetic. These isotopes are used in various fields such as medical science, agriculture, food preservation, and electricity generation.

3.10.1 Medical Science

• Diagnosis:

• Radioactive isotopes are used for diagnostic imaging. For example, Technetium-99 (Tc) is injected into the body. It accumulates in specific areas, emitting gamma rays. A gamma ray camera outside the body captures the emitted radiation to create an image of the affected area.

• Tc-99 has a half-life of 6 hours, which makes it safe as it loses its radioactivity quickly.

• Treatment of Diseases:

• Thyroid Cancer: The Iodine-131 (I-131) isotope is used to treat thyroid cancer. The patient drinks a solution containing I-131, which accumulates in the thyroid and emits beta rays, killing the cancerous cells.

• Brain Cancer: Iridium-192 (Ir-192) is used for treating brain cancer.

• Tumors: Cobalt-60 (Co-60) is used to both diagnose and treat tumors. Its emitted gamma rays target and destroy cancer cells.

• Leukemia: Phosphorus-32 (P-32) is used to treat leukemia.

3.10.2 Agriculture Sector

• Crop Nutrition:

• Radioactive isotopes help in determining the optimal amount of fertilizers like nitrogen and phosphorus. These isotopes are absorbed by plants and detected using Geiger-Müller counters, helping to ensure proper fertilization without excess or deficiency.

• Getting Rid of Harmful Insects:

• Radioactive isotopes help in determining the appropriate use of insecticides. These isotopes help regulate the amount of insecticides needed, reducing the harm they cause to the environment and non-target species.

• Development of Crops:

• Radioactive isotopes play a role in developing hybrid crop varieties by inducing genetic mutations. This leads to improved crop traits such as higher yield or resistance to diseases.

3.10.3 Generation of Electricity

• Nuclear Power Plants:

• Fission reactions (splitting atoms) release a large amount of heat energy. This heat is used to generate electricity in nuclear power plants. The Rooppur Nuclear Power Plant in Bangladesh is an example, expected to produce 2400 MW of electricity.

3.10.4 Impact of Radioactive Isotopes

• Positive Uses: Radioactive isotopes have many beneficial applications in medicine, agriculture, and electricity generation.

• Negative Impacts:

• Health Risks: Exposure to alpha, beta, and gamma radiation can cause genetic mutations, leading to cancers.

• Historical Disasters:

• Hiroshima and Nagasaki: The atomic bombs used during WWII caused massive loss of life and long-term radiation effects.

• Chernobyl (1986): A nuclear accident that caused widespread harm to people and the environment due to radioactive contamination.