For the same absorbed dose, which type of radiation causes a greater biological effect due to its radiation weighting factor (Wr)?

For the same absorbed dose, which type of radiation causes a greater biological effect due to its radiation weighting factor (Wr)?

• A. Gamma radiation
• B. Alpha radiation
• C. Beta radiation
• D. X-ray radiation

Answer: (B)

Radiation weighting factor (Wr) scales the biological impact of energy deposited by different types of radiation. For the same absorbed dose, the biological effect is larger when Wr is higher. Alpha particles have a Wr of about 20 because they’re highly ionizing and cause dense ionizations along a short path, leading to more complex and harder-to-repair DNA damage. Gamma rays, X-rays, and beta particles have Wr around 1, reflecting their lower ionization density per unit energy. So, with the same absorbed dose, alpha radiation produces a much greater equivalent dose and hence a greater potential biological effect.

Radiation weighting factor (Wr) scales the biological impact of energy deposited by different types of radiation. For the same absorbed dose, the biological effect is larger when Wr is higher. Alpha particles have a Wr of about 20 because they’re highly ionizing and cause dense ionizations along a short path, leading to more complex and harder-to-repair DNA damage. Gamma rays, X-rays, and beta particles have Wr around 1, reflecting their lower ionization density per unit energy. So, with the same absorbed dose, alpha radiation produces a much greater equivalent dose and hence a greater potential biological effect.