What material is used as shielding in radiology safety equipment?

• A. Aluminum
• B. Steel
• C. Copper
• D. Lead

Answer: (D)

In radiology shielding, the goal is to reduce exposure by absorbing X‑ray photons. Materials with a high atomic number and high density are most effective because they absorb photons more readily. Lead fits this role best; its dense, high‑Z composition provides strong attenuation per thickness, so a relatively thin layer can significantly cut X‑ray exposure and it can be shaped into aprons, curtains, and barriers for practical use.

For the same thickness, lead blocks more X‑rays than lighter or less dense materials, which is why it's the standard shielding material. Aluminum would need a much thicker layer to achieve the same protection, making it impractical. Copper and steel offer some attenuation but are less efficient than lead at diagnostic energies, so achieving equivalent protection would require greater thickness and weight.