Which statement about shielding is true?

• A. Shielding increases dose
• B. Shielding has no effect on dose
• C. Shielding is optional for all work
• D. Shielding reduces dose

Answer: (D)

Shielding reduces dose by acting as a barrier that absorbs or blocks radiation before it reaches you. The amount of reduction depends on the material, its thickness, and the energy of the radiation. Dense, high-Z materials like lead or thick concrete are used for gamma and x-ray shielding, while other materials may be suitable for different radiation types. The effectiveness is described by attenuation: as the shielding thickness increases, the dose that gets through drops, though some radiation will still penetrate depending on energy.

This is why shielding is a key part of keeping exposures as low as reasonably achievable. It works in concert with time and distance to minimize dose. The statement that shielding reduces dose is the true one, while the other options incorrectly claim shielding has no effect, increases dose, or is optional for all work.