Which statement correctly reflects the lens dose limit specified by NCRP?

• A. The lens dose limit is 150 mSv per year
• B. The lens dose limit is 5 mSv per year
• C. The lens dose limit is 50 mSv per year
• D. The lens dose limit is 500 mSv per year

Answer: (A)

The lens of the eye is unusually sensitive to ionizing radiation, so protecting it requires a specific dose limit for the eye rather than using the whole-body limit. For occupational exposure, NCRP sets the maximum equivalent dose to the lens at 150 mSv per year. This level helps keep the risk of radiation-induced cataracts acceptably low given typical radiographic work.

The other numbers don’t match NCRP guidance: 5 mSv per year is far too low for regular lens exposure in many radiography tasks, 50 mSv per year corresponds to more recent recommendations not aligned with NCRP’s traditional lens limit, and 500 mSv per year is far above what is considered safe for the eye.