ASNT Industrial Radiography Radiation Safety Practice Test

Which type of radiation is considered more damaging to human tissue?

1. Alpha particles

2. Beta particles

3. Gamma rays

4. X-rays

The correct answer is: Alpha particles

Alpha particles are considered more damaging to human tissue primarily due to their high mass and charge, which gives them a greater ionizing ability compared to other forms of radiation. When alpha particles interact with matter, they can cause significant ionization in a short range, leading to potential damage at the cellular level. Although alpha particles have a limited range and can be stopped by a piece of paper or even air, they become particularly hazardous when emitted by radioactive materials that enter the body through ingestion, inhalation, or wounds. Once inside the body, alpha particles can release a large amount of energy over a small area, resulting in increases in cellular damage and a higher likelihood of biological effects such as mutations or cancer. In contrast, beta particles, gamma rays, and X-rays have different penetrating abilities and energies that typically result in less localized damage. The damaging effects of radiation depend on several factors, including the radiation type, energy level, and how the exposure occurs, but in an internal exposure scenario with alpha emitters, their potential for damage to tissues is significantly higher.