What are the biological effects of alpha radiation?

Alpha radiation consists of heavy particles made up of two protons and two neutrons, which are emitted from certain radioactive materials. When alpha particles interact with biological tissues, they cause significant damage due to their large mass and charge, which allows them to transfer energy efficiently. However, alpha particles have very low penetration power and can be stopped by just a few centimeters of air or by the outer layer of skin.

The correct answer highlights the distinction in risk posed by alpha radiation depending on the route of exposure. While externally, the skin effectively protects against alpha particles, preventing them from causing damage, ingestion or inhalation of alpha-emitting materials can lead to severe biological effects. Once inside the body, alpha particles can directly damage cells and tissues, leading to potential health effects like radiation sickness or increased cancer risk due to the localized high-energy deposition in sensitive tissues.

This understanding is crucial in radiation safety practices, emphasizing the different safety protocols needed for handling materials that emit alpha radiation to prevent internal contamination, contrasting sharply with those needed for external exposure.