What does MRI use in combination with radio waves to create images?

MRI, or Magnetic Resonance Imaging, utilizes strong magnetic fields in conjunction with radio waves to produce detailed images of the internal structures of the body. The magnetic fields align the protons in hydrogen atoms within the body, primarily found in water and fat. When radio waves are applied, they disturb this alignment, and as the protons relax back to their original state, they emit signals. These signals are then captured and processed to create comprehensive images.

The reason why the other options are not applicable is that X-rays work based on different principles of ionizing radiation, while ultrasound waves use sound waves for imaging, and infrared waves involve heat radiation rather than magnetic resonance. Consequently, the combination of magnetic fields and radio waves is unique to MRI technology, allowing it to produce high-resolution images without exposing patients to ionizing radiation.