Question

In terms of classification of staff and designated areas, which of the following are true?

a. If an employee works in a supervised area, his external dose rate could be between 2.5 and 7.5 μSv h-1 averaged over the working day

b. If an employee works in a controlled area it means that the dose to the lens of his eyes could be more than 45 mSv

c. In a supervised area, it is likely that any person could exceed the dose limit for a member of the public

d. Of the staff in the radiology department, 99% do not exceed the dose limit of a member of the public in any year

e. If the finger monitoring of a radiologist showed that he received 150 mSv over the ** of a month, it means he needs monthly dose monitoring and an annual health check

Answer 1

a. True. In a supervised area, the dose rate is between 2.5 and 7.5 μSv h-1 averaged over the working day, while in a controlled area the dose rate could exceed 7.5 μSv h-1 .

b. True. The dose limit for the lens of the eyes is 150 mSv and a person working in a controlled area is likely to receive a radiation dose greater than three-tenths of any dose limit.

c. True.

d. True. Less than 1% of the staff in the radiology department whose dose is monitored receive more than 1 mSv in any year (dose limit for a member of the public).

e. True. A finger dose of more than 150 mSv per year means that the person should be classified. The monitoring ** for classified workers is 1 month and they must have an annual health check and the records of these should be kept for 50 years.