Which value represents the NCRP-recommended thyroid dose limit?

Which value represents the NCRP-recommended thyroid dose limit?

• A. 500 mSv
• B. 5 mSv
• C. 50 mSv
• D. 150 mSv

Answer: (A)

Organ-specific dose limits protect sensitive tissues from cumulative radiation exposure. The thyroid is particularly radiosensitive, so NCRP sets a yearly limit specifically for that organ. The recommended thyroid limit is 500 mSv per year, meaning the thyroid should not receive more than 500 mSv in a single year from all occupational sources. This is higher than the whole-body limit (50 mSv) because it targets the thyroid alone, and it’s more than the lens-of-eye limit (about 150 mSv) or a 5 mSv figure, which wouldn’t reflect practical organ protection. So the 500 mSv value is the NCRP-recommended thyroid dose limit.

Organ-specific dose limits protect sensitive tissues from cumulative radiation exposure. The thyroid is particularly radiosensitive, so NCRP sets a yearly limit specifically for that organ. The recommended thyroid limit is 500 mSv per year, meaning the thyroid should not receive more than 500 mSv in a single year from all occupational sources. This is higher than the whole-body limit (50 mSv) because it targets the thyroid alone, and it’s more than the lens-of-eye limit (about 150 mSv) or a 5 mSv figure, which wouldn’t reflect practical organ protection. So the 500 mSv value is the NCRP-recommended thyroid dose limit.