Which imaging modality does not use ionizing radiation?

Which imaging modality does not use ionizing radiation?

• A. Fluoroscopy
• B. Ultrasound
• C. MRI
• D. CT

Answer: (C)

Imaging that doesn’t involve ionizing radiation relies on energy forms other than X-rays. Magnetic resonance imaging achieves images using a strong magnetic field and radiofrequency pulses to excite hydrogen nuclei and detect their signals. This process does not produce ionizing radiation, unlike fluoroscopy and CT, which use X-ray beams and carry ionizing exposure. Ultrasound also avoids ionizing radiation, but MRI is the classic example of a non-ionizing modality with superb soft-tissue contrast. So, the modality that does not use ionizing radiation is MRI.

Imaging that doesn’t involve ionizing radiation relies on energy forms other than X-rays. Magnetic resonance imaging achieves images using a strong magnetic field and radiofrequency pulses to excite hydrogen nuclei and detect their signals. This process does not produce ionizing radiation, unlike fluoroscopy and CT, which use X-ray beams and carry ionizing exposure. Ultrasound also avoids ionizing radiation, but MRI is the classic example of a non-ionizing modality with superb soft-tissue contrast. So, the modality that does not use ionizing radiation is MRI.