When alpha emitters are inhaled or ingested, what hazard do they pose?

• A. External hazard
• B. Thermal hazard
• C. Acoustic hazard
• D. Internal hazard

Answer: (D)

When alpha emitters are inside the body, the danger comes from internal exposure. Alpha particles are heavy and highly ionizing, so once they are inhaled or ingested, they deposit most of their energy in the nearby tissues over a very short range. That means a high radiation dose can hit sensitive cells in the lungs, stomach, bones, or liver, increasing the risk of tissue damage and cancer. External exposure from alpha emitters is minimal because alpha particles can’t travel far in air or through skin, so the main hazard shifts from outside the body to inside. The other hazards listed aren’t relevant here: external hazard would be radiation coming from outside the body, thermal hazard would require noticeable heat production, and acoustic hazard isn’t related to radioactive decay. Preventing inhalation or ingestion is key to avoiding this internal hazard.