What type of decay does Technetium-99m undergo?

• A. Alpha decay
• B. Beta decay
• C. Isomeric transition
• D. Neutron emission

Answer: (C)

Technetium-99m undergoes isomeric transition, which is a specific type of decay involving the release of energy from an excited nuclear state to a lower energy state without changing the number of protons or neutrons in the nucleus. During this process, Technetium-99m transitions to a more stable form, Technetium-99, by emitting gamma radiation. This characteristic makes it particularly useful in medical imaging since the emitted gamma rays can be detected by gamma cameras, allowing for detailed visualization of internal structures and processes in the body.

Isomeric transition is favored in this context because it allows for a relatively low radiation dose to the patient while still providing high-quality images. This method of decay ensures that Technetium-99m has a suitable half-life (about 6 hours), making it practical for clinical use in various diagnostic procedures. The energy released during isomeric transition is significant as it is what enables the radiopharmaceutical to be effective in imaging without the hazards that come with more destructive types of decay like alpha or beta decay.