Fetal exposure in diagnostic radiology

The problem of possible radiation damage to the fetus or embryo as a result of diagnostic radiography during pregnancy, particularly in the early stages, is discussed. Recommendations of therapeutic abortion after fetal exposure require an adequate knowledge of the doses involved. In the absence of actual dose measurements or estimates, approximate exposure levels may be determined from the literature. A summary of published values for radiography involving the lower abdomen is given. Data is also presented from a series of fetal exposures resulting mostly from routine diagnostic radiography when pregnancy was not known at the time but was established later. Results of actual dose measurements using a phantom and of dose calculations based on published values are in reasonable agreement indicating that literature values of dose provide a satisfactory alternative to measurement. These data suggest that diagnostic radiography rarely, if ever, results in fetal exposures high enough to justify therapeutic abortion. (author)