West Coast EMT Block One Exam

Which type of rays easily penetrate through the human body and require lead or concrete for protection?

1. Alpha

2. Neutron

3. Gamma

4. Beta

The correct answer is: Gamma

Gamma rays are a form of electromagnetic radiation that possess a very high energy level and have no mass or charge. This allows them to penetrate various materials, including human tissue, quite effectively. When gamma rays encounter matter, they can pass through it without being significantly hindered, which is why specialized shielding material such as lead or concrete is required to protect against them. Lead is particularly effective because its dense atomic structure can absorb and scatter the energy of gamma rays, reducing their intensity. Concrete, being dense and thick, also provides a reliable barrier against gamma radiation. In comparison, alpha particles, which are relatively large and charged, cannot penetrate the skin, while beta particles have limited penetration abilities and can be stopped by materials like plastic or glass. Neutron rays, while they can penetrate materials to some extent, typically require different types of shielding, such as materials rich in hydrogen. Therefore, gamma rays stand out as the type that necessitates dense shielding like lead or concrete for effective protection.