Which approach best minimizes fetal radiation exposure during imaging of a pregnant patient?

• A. CT with intravenous contrast
• B. X-ray with no shielding
• C. PET-CT
• D. Non-ionizing modalities such as Ultrasound or MRI

Answer: (D)

The key idea is choosing imaging that does not involve ionizing radiation to protect the fetus. Ultrasound uses sound waves, and MRI uses magnetic fields with radiofrequency energy—both do not ionize tissues, so they do not expose the fetus to ionizing radiation. In contrast, CT and X-ray rely on ionizing radiation, and PET-CT combines radioactive tracers with CT, delivering radiation to the fetus. When clinically appropriate, non-ionizing modalities are preferred to minimize fetal exposure, with ultrasound and MRI offering safe imaging options during pregnancy.