Studies through the gravid uterus, such as radiographs of the abdomen and lumbar spine, result in a fetal dose of 1 mGy to 3.
The fetal dose for a CT head is 0 mGy and for a CT chest is 0.
The risk of such a deleterious effect has been calculated at 30 IQ points reduction for every sievert; the risk of induced fatal childhood malignancy from exposure at this stage of gestation has been calculated at 28 cases per 1000 per Sv (or 28 "excess" cases of childhood cancer in a population of 1 million exposed to a fetal dose of 1 mSv).
16) Among the frequently performed radiographic examinations that cause greatest fetal dose is an anteroposterior (AP) projection of the lumbosacral spine (fetal dose = 40 mrad).
Despite the estimated 10-fold lower fetal dose, mean levels of BaP-DNA adducts as determined by high-performance liquid chromatography-fluorescence were comparable in paired New York City newborn and maternal samples (0.
There are no data in humans on maternal versus fetal dose of PAHs.
These preliminary results indicate a need for further research, especially as the fetal dose
from maternal exposure is unknown.
Scenario 3--Estimated fetal dose between 1 and 5 rem.
Scenario 4--Estimated fetal dose greater than 5 rem.
According to the International Commission on Radiological Protection (ICRP) Publication 84, exposure to x-rays is medically warranted for the majority of patients and fetal risk is considered minimal) This publication includes a table with approximate fetal doses
showing that most standard radiographic studies have fetal doses
calculated as being less than 10 mGy (see Tables 1 and 2).
However, official estimates of fetal doses
after the Chernobyl explosion, even in the most contaminated regions of Germany, were < 1 mSv (UNSCEAR 2000), far below the presumed safe threshold.
A highly statistically significant excess relative risk (ERR) associated with a diagnostic X-ray examination of 40% was obtained from the Oxford Survey, but reliable estimates of fetal doses
appropriate for this study are not easily derived (Mole 1990).