Which statement accurately contrasts MRI and CT regarding radiation exposure?

Which statement accurately contrasts MRI and CT regarding radiation exposure?

• A. MRI uses ionizing radiation; CT does not
• B. MRI does not use ionizing radiation; CT does
• C. Both use ionizing radiation
• D. Neither uses ionizing radiation

Answer: (B)

MRI does not involve ionizing radiation, while CT uses ionizing X-ray radiation. MRI generates images through magnetic fields and radiofrequency energy that realign and detect protons in body water, so there’s no radiation dose from the imaging itself. CT sends X-ray beams through the body and measures how much they are attenuated; X-rays ionize tissue, yielding a patient radiation dose. Clinically, this means MRI is preferred when avoiding radiation is important (like in kids or for repeated imaging, or when soft-tissue contrast is key), whereas CT provides rapid imaging and excellent detail for bones and acute emergencies, with attention given to dose-reduction strategies and safety considerations.

MRI does not involve ionizing radiation, while CT uses ionizing X-ray radiation. MRI generates images through magnetic fields and radiofrequency energy that realign and detect protons in body water, so there’s no radiation dose from the imaging itself. CT sends X-ray beams through the body and measures how much they are attenuated; X-rays ionize tissue, yielding a patient radiation dose. Clinically, this means MRI is preferred when avoiding radiation is important (like in kids or for repeated imaging, or when soft-tissue contrast is key), whereas CT provides rapid imaging and excellent detail for bones and acute emergencies, with attention given to dose-reduction strategies and safety considerations.