Which statement correctly differentiates surface contamination from irradiation?

• A. Contamination means radioactive material on surfaces or skin; irradiation means exposure from radiation penetrating the body without contamination
• B. Contamination means external X-ray exposure; irradiation means radioactive material on surfaces
• C. Contamination means exposure from gamma rays only; irradiation means exposure to all radiation types
• D. Contamination means no exposure; irradiation means exposure

Answer: (A)

The main idea is distinguishing when radioactive material is actually present on or on the surface of the body versus the body being exposed to radiation from a source without that material being deposited on you. Contamination means radioactive material is on surfaces or skin, and it can transfer to you or others and cause exposure through contact or transfer to the body. Irradiation means exposure to penetrating radiation that affects the body without having radioactive material deposited on it, such as external sources of radiation. The statement that captures this distinction is the one that defines contamination as material on surfaces or skin and irradiation as exposure from penetrating radiation without contamination. The other choices mix up what contamination and irradiation involve (external exposure, limited to gamma, or implying no exposure when there can be).