Isotopes that emit \(\alpha\) radiation are relatively safe outside the body and exceptionally hazardous inside. Explain why.

Ionizing radiation refers to energy forms that can detach electrons from atoms or molecules, thereby ionizing them. This type of radiation comes in various forms, including alpha particles, beta particles, gamma rays, and X-rays. Each type has a unique interaction with matter, and its ionizing power determines its ability to cause chemical changes in materials, including living tissues.

When ionizing radiation passes through biological tissue, it can disrupt cellular function by breaking molecular bonds. This can lead to mutations, cell death, tissue damage, and can increase the risk of cancer. Due to its potential to cause significant biological harm, safety measures are crucial when handling sources of ionizing radiation, and understanding the characteristics of each type is key to determining appropriate protective measures.

Alpha particles are composed of two protons and two neutrons bound together into a particle identical to a helium-4 nucleus. They carry a +2 charge, making them highly ionizing when they come into contact with other atoms and molecules.

Due to their mass and charge, alpha particles have a very short range in air and can be easily stopped by a sheet of paper or the outer layer of human skin. In the environment, they pose a minimal threat as their penetration power is not sufficient to penetrate external barriers effectively. However, their ionizing potential is significant, meaning that if alpha particles reach sensitive living tissue, they have the potential to cause serious damage.

Radiation penetration power refers to the ability of different types of radiation to pass through materials. Alpha particles have much lower penetration power compared to other forms of ionizing radiation like beta particles or gamma rays. Hence, they are generally unable to penetrate the human skin and require internal proximity to biological tissues to pose a significant health risk.

Materials of varying thickness and density can be used to shield against alpha radiation. For example, while a simple piece of paper may stop alpha particles, denser materials are necessary to block more penetrating forms of radiation, such as gamma rays. The penetration power is a crucial factor in safety practices, as it informs the type of shielding required and the potential for exposure.

Internal exposure to alpha radiation is particularly hazardous because alpha particles emit a high ionization potential within a short range. When alpha-emitting isotopes are inside the body, they can cause extensive damage to cells and DNA since they are in close proximity to tissues.

Internal exposure can occur through inhalation, ingestion, or absorption of radioactive materials into the body. Once inside, these materials can break chemical bonds and disrupt normal cell operations, leading to serious health issues such as cell death, cancer, and genetic mutations. Safety protocols aim to prevent internal exposure by using protective equipment, proper handling procedures, and monitoring to minimize the consequences of accidental ingestion or inhalation of radioactive materials.