Footnote
b The sievert is a measure of the amount of energy that radiation imparts to body tissues. One millisievert (mSv) is a thousandth of a sievert. The average annual dose in Britain is about 2 mSv, and a chest X ray gives about 0.1 mSv.
b The sievert is a measure of the amount of energy that radiation imparts to body tissues. One millisievert (mSv) is a thousandth of a sievert. The average annual dose in Britain is about 2 mSv, and a chest X ray gives about 0.1 mSv.