Which statement about alpha contamination is true?

Which statement about alpha contamination is true?

• A. Alpha limits are lower due to the high RBE of Alpha
• B. Alpha RBE is lower than gamma
• C. Alpha is an external exposure hazard only
• D. Alpha contamination has no health risk

Answer: (A)

Alpha radiation has a high linear energy transfer, meaning it delivers a large amount of energy over a very short path in tissue. Because of this high potency, any alpha contamination has a much greater potential biological effect if it is inhaled or ingested, so the permissible levels for alpha contamination are kept very low to protect workers from internal doses. External exposure from alpha sources is minimal since alpha particles cannot penetrate the skin, so the main concern is internal exposure. The other statements don’t fit: the RBE of alpha is not lower than gamma (it’s higher), alpha is not solely an external hazard, and alpha contamination does carry health risk.

Alpha radiation has a high linear energy transfer, meaning it delivers a large amount of energy over a very short path in tissue. Because of this high potency, any alpha contamination has a much greater potential biological effect if it is inhaled or ingested, so the permissible levels for alpha contamination are kept very low to protect workers from internal doses. External exposure from alpha sources is minimal since alpha particles cannot penetrate the skin, so the main concern is internal exposure. The other statements don’t fit: the RBE of alpha is not lower than gamma (it’s higher), alpha is not solely an external hazard, and alpha contamination does carry health risk.