Which imaging modality uses strong magnetic fields rather than ionizing radiation?

Which imaging modality uses strong magnetic fields rather than ionizing radiation?

• A. Ultrasound
• B. Magnetic resonance imaging
• C. X-ray
• D. Computed tomography

Answer: (B)

Strong magnetic fields are used to produce images in this modality. Magnetic resonance imaging uses a powerful static magnetic field (and radiofrequency pulses) to align and then detect signals from hydrogen protons in tissues, creating detailed soft-tissue contrast without ionizing radiation. In contrast, X-ray and computed tomography rely on ionizing X-rays, which carry radiation exposure. Ultrasound uses high-frequency sound waves and does not involve ionizing radiation either, but it does not rely on magnetic fields. Thus, this imaging method uniquely depends on strong magnetic fields rather than ionizing radiation.

Strong magnetic fields are used to produce images in this modality. Magnetic resonance imaging uses a powerful static magnetic field (and radiofrequency pulses) to align and then detect signals from hydrogen protons in tissues, creating detailed soft-tissue contrast without ionizing radiation. In contrast, X-ray and computed tomography rely on ionizing X-rays, which carry radiation exposure. Ultrasound uses high-frequency sound waves and does not involve ionizing radiation either, but it does not rely on magnetic fields. Thus, this imaging method uniquely depends on strong magnetic fields rather than ionizing radiation.