Diagnostic radiography in pregnancy: risks and reality.

BACKGROUND: The use of X-rays, computed tomography scanning and nuclear medicine imaging in the pregnant woman is a source of great anxiety for the patient, her family and the treating doctor.
METHODS: A literature review of appropriate databases, articles and relevant institutional protocols was performed. Data was sought regarding any adverse effects of diagnostic radiation in pregnancy, fetal absorbed dose of diagnostic radiation and how the timing of exposure and form of administration might influence these effects.
RESULTS: The estimated radiation dose for a fetus from background sources as well as medical imaging was identified. Most diagnostic radiation procedures will lead to a fetal absorbed dose of less than 1 mGy for imaging beyond the abdomen/pelvis and less than 10 mGy for direct or nuclear medicine imaging. Potential adverse outcomes related to radiation exposure during pregnancy include teratogenicity, genetic damage, intrauterine death and increased risk of malignancy. The only adverse effect statistically proven at the dose levels associated with diagnostic radiation procedures is a very small increase in childhood malignancy, with an estimated increase of one additional cancer death per 1700 10 mGy exposures. The important exception was the risk to the fetal thyroid from radioiodine exposure after 12 weeks' gestation.
CONCLUSION: In practice, diagnostic radiography during pregnancy not involving direct abdominal/pelvic high dosage, is not associated with any significant adverse events. Counselling of pregnant women who require diagnostic radiographic procedures as well as those inadvertently exposed should be based on the available human data with an emphasis on the minimal impact of such procedures.