Radioisotope

• Pronounced RAY-dee-oh-I-suh-tope, radioisotope is an unstable form of a chemical element that releases radiation as it breaks down and becomes more stable.
• Radioisotopes may occur in nature or be made in a laboratory.
• In medicine, they are used in imaging tests and in treatment.
• Also called radionuclide.

How are isotopes generated?

• Isotopes can either form in one of two ways
• spontaneously (naturally) through radioactive decay of a nucleus (i.e., emission of energy in the form of alpha particles, beta particles, neutrons, and photons) or
• artificially by bombarding a stable nucleus with charged particles via accelerators or neutrons in a nuclear reactor. In some cases, a new isotope of the same element is produced.

What is transmutation?

• In some cases, an element is converted to another element in a process called "transmutation."

How do they decay?

• As radioisotopes naturally decay, particles deposit (i.e., lose) energy onto materials such as air, water, and people as it passes through them.

How to be protected?

• Alpha particles energy is deposited across the shortest distance and, therefore, is "stopped" the most easily.
• Beta particles require slightly more protection, and photons (gamma rays and X rays) need much greater shielding.
• Neutron radiation is considered the most severe and dangerous to humans due to its high kinetic energy, so it typically requires the most significant shielding.

Materials for shielding

• Materials with low atomic numbers (water, carbon, lithium, etc.) that can slow neutrons down usually offer the most effective shielding.

Radioisotope Resources
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