Radiology General f480b585 Mean exposure of radiation from OPG is: A 300 mR B 90 mR C 0.03 mR D 30 mR High-Yield Explanation Mean exposure of skin from IOPA is 800 mR. Gonadal exposure is 1/10,000 of skin exposure i.e., 0.03 mR. Mean exposure of radiation from OPG is 90 mR.