Considerations for Patients Exposed More Than 15 Weeks Postconception

Potential risks to the developing central nervous system for women who are more than 15 weeks postconception exist only at high doses (e.g., more than 200 mGy) well beyond those commonly delivered in multiple diagnostic examinations. For women in this period the only risk to the fetus from diagnostic doses of radiation is induced cancer. The cancer risk from well-managed radiologic procedures is too small to warrant any medical intervention. The lifetime attributed cancer incidence for a conceptus/fetal dose of 50 mGy in this gestational period is roughly estimated at 2%, but an accurate quantification is impossible [19,20]. Conversely there is about a 98% likelihood the child will be unaffected by the radiation. Most diagnostic examinations result in much less dose to the conceptus/fetus. Abdominal/pelvic CT imaging, which is one of the higher dose examinations, typically delivers 20 to 35 mGy.