Radiation dose to the fetus in obstetric radiography

The mean dose to the fetus and fetal head, together with the doses to the fetal gonads and maternal gonads, have been estimated to be 107, 56, 131 and 136 mrad respectively for an obstetric prone oblique examination of the abdomen, using a rare-earth screen-film combination. The doses were derived by measuring skin doses on a series of women in late pregnancy undergoing the above examination and by using measured depth-dose information. The position of the fetus relative to the maternal skin surface was determined by ultrasonic scanning.